Part I. New Project: SKANTIC M # ULAR CTVs SILICON DIODE CAMERA TUBES TV FAULT REPORT VCR CLINIC SERVICING FREQUENCY COUNTER TIMER

Transcription

1 APRIL -'11983 AustraIiall 74 New Zealand $2 00- Malaysia $5 50 I R Et 33 (inc VAT) 913p SERVICINGMONCONSTRUCTIONDEVELOPMENTS New Project: FREQUENCY COUNTER TIMER Part I SERVICING SKANTIC M # ULAR CTVs SILICON DIODE CAMERA TUBES TV FAULT REPORT VCR CLINIC

2 Interested in Television Servicing? Try a ZED Pack. Effect Repairs at Minimum Cost. Z mixed I and f watt and miniature resistors f 1.95 Z2 150 mixed 1 and 2 watt resistors 1.95 Z3 300 mixed capacitors, most types amazing value 3.95 Z4 100 mixed electrolytics 2.20 Z5 100 mixed Polystyrene Capacitors 2.20 Z6 300 mixed Printed Circuit Components 1.95 Z7 300 mixed Printed Circuit resistors 1.45 Z8 100 mixed High Wattage Resistors, wirewounds etc Z9 100 mixed Miniature Ceramic and Plate caps 1.50 Z Assorted Potentiometers 1.50 Z11 25 Assorted Presets, Skeleton etc. Z12 20 Assorted VDR's and Thermistors 1.20 Z13 I lb Mixed Hardware, Nuts, Bolts, Selftappers, "P" clips etc Z mixed New and marked transistors, all full spec. includes: PBC 108, BC148, BF154, BF274, BC 1 21L, BC 238, BC 184L and/or Lots of similar types ONLY 4.95 (Z 14A) 200 Transistors as above but including power types like BD 131, 2N3055, AC 128, BFY50 etc Z Mixed Diodes including: Zener, Power, Bridge, Signal, Germanium, Silicon etc. All full spec Z16 201N4148 Gen Purpose Diodes Z17 20 IN4003/10D2 Z18 20 Assorted Zeners. I watt and 400 mw High quality COAX PLUGS, silver plated pin, grub screw fixing. 5 for 1 COAX COUPLERS 5 for 1 COAX FLYING SOCKET 3 for 1 ELECTROLYTIC 1pf 63v 20 for 350v 10 for 2.2pf 63v 20 for 4pf 350v 10 for 22p,f 16v 20 for 100pf 25v 20 for pf 25v 20 for µf 25v 10 for 400µf 40v' 8 for 4/0p.f 25v 10 for 470µf 35v 8 for 1000pf 35v 6 for Axial. All others are Radial. CAN TYPES 22pf 375v (3 pin) v (3 pin) v 2000µf 100v v 60p Z20 Z2I Z22 Z23 Z24 Z25 Z26 Z27 Z28 Z29 Z EHT DIODES Very small. 20kV 2.5ma. 30ma peak ea. 3 for R.B.M. USERS LOOK! No more messy soldering. 24 pin I.C. sockets for SL901 etc. SPECIAL OFFER: 5 for f for SPECIAL OFFERS 100 Assorted Polyester Capacitors. Mullard C 296's and others I 60v -400v only Assorted Mullard C 280's Cosmetic imperfects etc Mallard Miniature Electrolytics Cosmetic imperfects etc PACK OF EACH V BULBS on leads. Suitable for most VIDEO RECORDERS. 90p each 3 for 2.50 BY127 Type diodes. Unmarked, 2,200µf 40v 60p untested, Approximately 90% 2,2000.f 63v 70p o.k. 100 for , v AC128 untested 100 for ,500µf 35v 60p 2.f 400v ITT/RBM THEY'RE BACK We can now again offer our special TV BARGAIN PARCELS. These contain all manner of useful bits and pieces. Components, semiconductors. videogame boards etc. which we have accumulated over the past year and must clear as we need the space. 5kg kg "RIFA" 0. I p 1000v Flameproof 5 for 10 Assorted switches including: Pushbutton, Slide, Multipole, Miniature etc. Fantastic Value 100 Assorted Silver Mica caps 10 Mixed TV convergence Pots 20 Assorted TV Knobs including: Push Button, Aluminium and Control types 10 Assorted Valve bases B9A, EHT, etc. 10 Spark Gaps 20 Assorted Sync Diode Blocks 12 Assorted IC Sockets 20 General Purpose Germanium Diodes 20 Assorted Miniature Tantalum Capacitors. Superb Buy at 40 Miniature Terry clips, ideal for small Tools etc. 5 CTV Tube Bases 10 EY87/DY87 EHT bases 20x PP3 Battery Connectors 6 x Miniature "Press to Make" Z31 Z32 Z33 Z34 Switches, Red Knob f 1.00 Z35 12 Sub Min S.P.C.O. Slide Switches Z36 12 Min D.P.C.O. Slide Switches Z37 8 Standard 2 Pole 3 Pos Switches f LIM Z38 4 x HP11 Batt Holders (2 x 2 Flat type) 4 for f1.00 Z39 3.5mm Jack Sockets, switched, enclosed Type 8 for Z Miniature Reed Switches Z Subminiature Reed Switches 4.20 Z42 20 Miniature Reed Switches Z43 12 Subminiature Reed Switches ZENER DIODES Ov 7. 2v7, 4v3, 4v7, 5v6, 6v2, 6v8, 7v5.27v,30v. ALL 400mw. 10 of one value 10 of each 1.3 watt. 12v, I 3v. I 8v 10 of one value 10 of each flop DIODES 25 x IN for x IN for x IN for E x 1N for x IN x SKE 41'2/06 (600v 2a fast switching) ELM 12 xby127 8 x BY255 (3A 1000V) 10 x BA158 (600v 400ma) IN5402 3a 200v 8for 6A. 100V. Bridge Rectifier. Very small. 80p ea. 3 for 2.00 I.C.'S CA270AEf for C5.00 MC1327P 6 for/5.00 TBA I 20SB each, 5 for 2.00 TBA820 El each, 6 for E5.00 TBA810P 6 for Timer 4 for TAA 66113f for C5.00 SN76660N 5 for 2.00 THORN SPARES "3500"Transductor "3500" Focus Assembly with VDR "8500" Focus Assembly. Rotary type "8500" v Line Capacitor "1590/91" Portable metal boost Diode (W 11) "1500" Bias Caps v "1500" Jellypot. L.O.P.T. Pinkspot "900/950" 3 stick triplers "950" Can µf THYRISTOR CONVERGENCE POTS 511, SS 106 (BT106) 75p each I K. 8 of one type. 8 of 3 for 2.00,10 for 5.50 each type Z44 TO3 Mounting kits (BU208) 8 for 60p Z45 T0220 Mounting kits (TIP33) 10 for 60p Z46 TO126 Mounting kits (BD131) 12 for 60p Z47 Pack of each Mounting kit. All include insulators and washers 1.50 Z48 3a 1000v Diodes (IN5408 type) 8 for Z49 Brushed Aluminium Push Button Knobs, 15mm long x I 1mm Diam. Fit standard 34 -mm square shafts 10 for Z50 Chrome finish lomm x lomm Diam as above 10 for Z51 Aluminium Finish. Standard Fitting Slider Knobs. (Decca) 10 for Z52 Decca "Bradford" Control Knobs Black and Chrome. 1" Shaft 8 for Z53 Tuner P/B Knobs, Black and Chrome. Fit most small Diam Shafts, ITT, THORN, GEC etc. 8 for f1.00 Z54 Spun Aluminium Control Knobs (ITT) 4" Shaft, suitable for most sets with recessed spindles 8 for Z55 14 Pin DIL I.C. Sockets 12 for Z56 16 Pin Quil I.C. Sockets 12 for f 1.00 Z57 16 Pin DIL TO QUIL I.C. Sockets 10 for Z58 22 Pin DIL I.C. Sockets 10 for OM Z59 B9A Valve Bases P.C. Type 20 for f 1.00 Z i Watt Emitter Resistors 40 for V.C.R. BATTERY PACKS. HITACHI PORTABLE V.C.R. Nicad pack. Type VTBP6OE 20 each. Brand New and Boxed 3 for 50 THORN "VIDEOSTAR" 3V25/26 Nicad pack. Type VA214. Also suitable for J.V.C. etc. These are untested units which contain 10 X "C" size (HP11) Nicads, which alone would cost in excess of 20. A Real Bargain at 10 each 3 for 25 MISCELLANEOUS BG 00 tripler for CVC45 etc. Line output transformer for only 3.50 RBM823A 4.25 each, 3 for ITT VC200 4P/13 Transistor Tuner. Suitable for some Pye and Philips sets. 3 hole fixing 2.75 each Decca Bradford Tuner. 5 button type 4.00 each, 4 for UHF Modulator UHF out Video in. Ch "x2"x1" complete with 9 foot coaxial lead and plug. With connection data 3.00 each, 2 for 5.00 GEC Hybrid 2040 series Focus Assembly with lead and VDR rod 2.00 each, 3 for 5.00 Convergence Panel for above. Brand new leads and plug each GEC 2010 Transistor Rotary Tuner with AE, SKT, and leads 1.95 each, 3 for 5.00 Buch CTV 25 Quadrupler type Q25B equivalent to ITT TU25 3QK 3.00 each, 2 for 5.00 Focus VDR Rods 2i" x I". Suitable for GEC, Decca etc. 75p each, 3 for 2.00 Grundig UHF/VHF Varicap Tuner for 1500GB, 3010GB each, 3 for EHT Lead with Anode cap (CTV) suitable for split Diodes sets lm long 60p each, 3 for 1.50 EHT Cable per metre, 10 metres 2.50 Anti Corona Caps 3 for Mhz CTV Crystals each, 3 for 2.50 Cassette Mains Leads. 7ft with fig 8 plug 60p each, 3 for MHZ sound filters, ceramic 3 pin "TAIYO" type each, 3 for 10.7 MHz Ceramic Filters "Vernitron" FM4 each, 3 for PYE CT200 Control Knobs 8 for Cassette/Calc Leads. 2m long, figure 8 skt. to flat pin. EI.20,3fm American plug 60p each, 3 for , 3 for foril 00 5 fort fqrfl 5 O 3.5mm Jack Plug on 2m of screened lead Degaus VDRs. 11. diam, for RBM etc. Mams Neons 2k2 Screenfeed Resistors. White ceramic, 9 watt, with fusible link. 5 for 5 for 10 for 8 for 3.5 O Philips G8 Transductor. ILIA 3 for 3.00 each,, 3 for L2.5 E.H.T. Discharge probe, with heavily insulated handle, O f1.00 with lead and chassis connector. 60p each, 3 for 1.50 REGULATORS 7812 I2v I a 3 forf v la 3 for GEMINI ELECTRONIC COMPONENTS Dept. TV, The Warehouse, Speedwell Street, London S.E.8. Please quote ZED code where shown. Send cheque* or Postal Order. Add 60p P&P and 15% VAT. *Schools etc. SEND OFFICIAL ORDER. Allow upto 28 days for delivery. Most orders despatched same day. ZED PACKS now available forcallers at 50 Deptford Broadway, London, S.E.S. Send large SAE. for list of Quantity, Prices and Clearance Lines etc.

3 71F Eli April Vol. 33, No Issue 390 COPYRIGHT 'IPC Magazines Limited, 1983, Copyright in all drawings, photographs and articles published in Television is fully protected and reproduction or imitation in whole or in part is expressly forbidden. All reasonable precautions are taken by Television to ensure that the advice and data given to readers are reliable. We cannot however guarantee it and we cannot accept legal responsibility for it. Prices are those current as we go to press. CORRESPONDENCE All correspondence regarding advertisements should be addressed to the Advertisement Manager, "Television", King's Reach Tower, Stamford Street, London SE1 9LS. Editorial correspondence should be addressed to "Television", IPC Magazines Ltd., Lavington House, 25 Lavington Street, London SE1 OPF. SUBSCRIPTIONS An annual subscription costs 11 in the UK, 12 overseas (by surface mail). Send orders with payment to IPC Services, Oakfield House, Perrymount Road, Haywards Heath, Sussex. BINDERS AND INDEXES Binders (E4.50) and Indexes (45p) can be supplied by the Post Sales Department, IPC Magazines Ltd., Lavington House, 25 Lavington Street, London SE1 OPF. Prices include postage and VAT. In the case of overseas orders, add 60p. BACK NUMBERS Some back issues are available from the Post Sales Department, IPC Magazines Ltd., Lavington House, 25 Lavington Street, London SE1 OPF at 85p inclusive of postage and packing. QUERIES We regret that we cannot answer technical queries over the telephone nor supply service sheets. We will endeavour to assist readers who have queries relating to articles published in Television, but we cannot offer advice on modifications to our published designs nor comment on alternative ways of using them. All correspondents expecting a reply should enclose a stamped addressed envelope. Requests for advice in dealing with servicing problems should be directed to our Queries Service. For details see our regular feature "Service Bureau". Send to the address given above (see "correspondence"). this month 289 Leader 290 Teletopics News, comment and products of TV interest. 292 Fault Report Notes on TV faults and servicing matters contributed by Nick Lyons, Richard Roscoe and Mick Dutton. 296 N1700 Speed Conversion by Mike Phelan Since the Philips N1700 series machines have d.c. motors conversion for half speed working is reasonably easy to achieve. The result is increased tape economy with scarcely any loss of picture quality. 298 Letters 300 Routine TV Receiver Tests by S. Simon The Thorn 8000A, 8500 and 8800 chassis plus notes on c.r.t. heater isolation. 301 Next Month in Television 302 VCR Clinic Notes on VCR faults and servicing contributed by Steve Beeching, T.Eng. (C.E.I.), Derek Snelling, Richard Roscoe and Mike Phelan. 304 Miller's Miscellany by Chas E. Miller Comments on the TV scene and a further episode in the saga of Ike Hodge. 306 Frequency Counter -Timer, Part 1 by Tony Jenkins The aim with this new project has been to provide a versatile digital counter -timer at an economical cost. Construction is simplified by the use of a triplexed LCD display. 310 Servicing Skantic Modular CTVs by John Brown A comprehensive run-down on faults encountered with the Skantic 4751/5151/5661 and related models. The power supply was the subject of a previous article. 312 Simple VCR Servicing, Part 3 by Derek Snelling This concluding instalment deals with the no fast forward or rewind conditions. 314 Modern CCTV Camera Tubes by Peter Graves The construction, operation and main characteristics of the silicon diode array tube and the silicon intensifier tube. 316 Now and Then by Les Lawry -Johns Amongst other things the King gives guidance on Mrs. Earlybird's music centre. 318 Long-distance Television by Roger Bunney Reports on DX reception and conditions and news from abroad. Also details of a converter to enable 5 5 and 6 5MHz intercarrier sound signals to be tuned in on an f.m. radio receiver. 321 Service Bureau 322 Test Case 244 OUR NEXT ISSUE DATED MAY WILL BE PUBLISHED ON APRIL 20 TELEVISION APRIL

4 MANOR SUPPLIES NEW MKV CHEQUERBOARD & PAL COLOUR TEST GENERATOR FOR TV & VCR. TEST DEMONSTRATIONS AT 172 WEST END LANE ups * 40 different patterns and variations. * Broadcast transmission accuracy (fully interlaced sync pulses with correct picture blanking). EBU colour bars, BBC colour bars, whole rasters & split bars (specially useful for VCR service), white, yellow, cyan, green, magenta, red, blue and black. * Chequerboard. * Mono outputs with border castellations, cross hatch, grey scale, vertical lines, horizontal lines and dots. UHF modulator output plugs straight into receiver aerial socket. * Additional video output for CCTV & VCR. * Facilities for sound output. * Easy to build kit. Only 2 adjustments. No special test equipment required. * Mains operated with stabilised power supply. * All kits fully guaranteed with back-up service. * Also available with VHF Modulator. Price of Kit Standard Case (101" x 64" x 24") 5.50 DeLuxeCase(10dx 6"x 2r) 8.50 Optional Sound Module (6MHz or 5.5MHz) 4.50 Built & Tested in De Luxe Case including Sound Module ST.. CIA a I REPORT 1 Post/Packing a All above prices include VAT 15% LTELEVISION' c PAL COLOUR BAR GENERATOR (Mk 4) 11;11 DC L...cif 4TH SUCCESSFUL YEAR * Output at UHF, applied to receiver aerial socket. * In addition to colour bars R -Y, B -Y etc. * Cross -hatch, grey scale, peak white and black level. * Push button controls, battery or mains operated. * Simple design, only five i.c.s. on colour bar P.C.B. PRICE OF MK 4 COLOUR BAR GENERATOR KIT DELUXE CASE BATT HOLDERS 3.20 OR MAINS SUPPLY KIT 4.80 (Combined P&P 1.80). MK 4 DE LUXE (BATTERY) BUILT & TESTED P & P. MK 4 DE LUXE (MAINS) BUILT & TESTED P & P. VHF MODULATOR (CHI to 4) FOR OVERSEAS EASILY ADAPTED FOR VIDEO OUTPUT & C.C.T.V. (ALL PRICES INCLUDE 15% VAT) MANOR SUPPLIES TELETEXT ADAPTOR KITS MK 1 (Texas XMII) Cable remote control p.p MK 2 (Philips/Mullard) Infra -red remote control p.p Further details on request. Goods available if in stock immediately over shop counter (Mail order between 3 days and I week from receipt of order). MI MI a TV SERVICE SPARES BACKED BY TWENTY YEARS EXPERIENCE & STAFF OF TECHNICAL EXPERTS TELEVISION MAGAZINE PROJECT PARTS NEW COLOUR PORTABLE TV TV PATTERN GENERATOR SMALL SCREEN MONITOR MONO PORTABLE TV LARGE SCREEN COLOUR TV PHONE, CALL, OR SEND FOR LISTS WORKING MODELS & PANEL TEST SERVICE AT 172 WEST END LANE. SAW FILTER IF AMPLIFIER PLUS TUNER COMPLETE AND ested for T.V. SOUND & VISION p.p (SUITABLE FOR USE WITH TELEVISION SIGNAL BOARDS). TV SOUND IF PANELS, FULLY TESTED 7.82 p.p.. SPECIAL OFFER TEXAS XMII TELETEXT MODULE NEW & TESTED, AT REDUCED PRICE p.p PHILIPS-PYE Gil TYPE TELETEXT DECODERS p.p TELETEXT 23 BUTTON DE -LUXE HANDSET WITH 5 YDS. CABLE 7.80 p.p XMII STAB. POWER SUPPLY 4.40 p.p CROSS HATCH UNIT KIT, AERIAL INPUT TYPE, INCL. T.V. SYNC AND UHF MODULATOR. BATTERY OPERATED. ALSO GIVES PEAK WHITE & BLACK LEVELS. CAN BE USED FOR ANY SET E12.65 p.p. 60p. (ALUM CASE 2.60 DE LUXE CASE 5.50 p.p ) ADDITIONAL GREY SCALE KIT 3.35 p.p. 45p. UHF SIGNAL STRENGTH METER KIT (VHF version also available). ALUM CASE 2.60 DE LUXE CASE 8.50 p.p CRT TESTER & REACTIVATOR PROJECT KIT FOR COLOUR & MONO p.p BUSH A823 POWER BASIC PCB. IN FIBREGLASS 6.40 p.p. BUSH Z718 BC6100 SERIES IF PANEL 5.75 p.p. 90p. BUSH A816 IF PANEL (SURPLUS) f1.90 p.p. 90p. DECCA "Bradford" IF T.B. POWER ex rental 5.75 each p.p DECCA 80, SERIES, IF FRAME T.B each p.o GEC 2110 Decoder, RGB panels (ex rental) 5.75 each p.p.. GEC 2040 DECODER PANEL 2.88 p.p GEC 2040 IF PANEL 3.22 p.p. f THORN TX9 PANELS ex factory for small spares. Includes I.C.s & Semiconductors etc p.p THORN TX9 PANELS salvaged ex factory for spares Intl LOFT & mains transformers p.p THORN 3000 LINE T.B., POWER PCB 5.75 each p.p THORN 3000 CONVERGENCE PANEL 5.75 p.p THORN 3000 VID, IF, DEC, Ex Rental 3.70 each p.p THORN 8800 Varicap channel selector & front control unit 4,37 p.p THORN 8000/8500 IF/DECODER PANELS salvaged 3.70 p.p THORN 8000/8500 FRAME T.B. PANELS salvaged/spares 2.88 p.p THORN 9000 SERIES TOUCH TUNE REMOTE CONTROL UNIT PLUS ULTRASONIC TRANSMITTER HANDSET p.p THORN 9000 IF/DECODER PANELS Salvaged 5.75 p.p PHILIPS 210, 300 Series Frame T.B. Panels 1.15 p.p. 80p. PHILIPS G8/G9 IF/DECODER Panels for small spares 1.75 p.p G8 IF Panels for small spares 1.15 p.p. 95p. 08 Decoder panels salvaged panels for spares 2.00 p.p G9 Scan Panel. Basic PCB in fibreglass p.p VARICAP, U321, U322, ELC 1043/06 ELC 1043/ p.p. 80p; G.I. type (equiv. 1043/05) MAO p.p. 60p. MAKERS VARICAP CONTROLS 8e CT200 4PSN 8.60, A823 4PSN 5.50, M' CVC5 7PSN 7.82 etc. p.p. P. SPECIAL OFFER ELEVEN POSITION VARICAP CONTROL UNIT UHF/VHF 2.10 p.o.. BUSH "Touch Tune" Varicap Control Z179, Z718 types 4.40 p.p. 95p. VARICAP UHF -VHF ELC 2000S BUSH TYPE 7.82 p.p. 85p. VARICAP VHF MULLARD ELC p.p. 80p. UHF/625 Tuners, many different types in stock. UHF tuners transisted. incl. s/m drive, Mullard 4 position push button 4.80 p.p LOPTS NEW & GUAR. P/P Mono 1.35p, Colour 1.45p, Bobbins 80p. BUSH 161 to 186 (twin panel) 6.80 R.B.M. A BUSH, MURPHY 774 series 9.80 R.B.M. Z BUSH, MURPHY A816 series 9.80 R.B.M. T20, T DECCA 20/24, 1700, 2000, R.B.M. T20, T22 Bobbin 6.44 FERG- HMV, MARCONI, ULTRA DECCA Bradford tun.mmn _ , 1400, 1500, DECCA 80, THORN 1600, , GEC GEC 2000 to 2038 series 7.80 GEC GEC series I & GEC 2110 Series INDESIT 20/24EGB 8.80 ITT CVC 5 to ITT/KB VC 200, 300 ism ITT CVC MURPHY 1910 to 2414 series 6.80 ITT CVC25, CVC30 series PHILIPS I9TG 170, 210, PYE PYE, INVICTA, EKCO, FERR. PYE 713, 715, 731 to , 169, 569, 769 series 8.80 PYE 725 (90 ) PHILIPS G8, G SPECIAL OFFER PHILIPS GEC 21 I4J/Junior Fineline 3.25 THORN 3000/3500 SCAN, EHT 7.85 PYE 40, THORN 8000/8500/ KB VC ELEVEN (003) 2.00 THORN 9000 to KB VCI 3.25 OTHERS AVAILABLE, PRICES ON REQUEST. ALSO F.OPTS. TRIPLERS Full range available. Mono & Colour. Special Offer: Thorn stick EHT Tray 1.72 p.p. 65p. TRANSDUCTORS suitable for 08, A823, Bradford etc p.p. 60p. 6.3V CRT Boost Transformers 5.80, Auto Type 3.20, p.p CALLERS WELCOME AT SHOP PREMISES Telephone /7346 THOUSANDS OF ADDITIONAL ITEMS AVAILABLE, ENQUIRIES INVITED LARGE SELECTION TESTED COLOUR PANELS POPULAR MODELS MANOR SUPPLIES 172 WEST END LANE, LONDON, N.W.6. NEAR: W. Hampstead Tuba Stn. (Jubilee) Bums 28, 159, C11 pass door W. Hampstead British Rail Snit (Richmond, Broad St.) (St. Pancras. Bedford) W. Hampstead (Brit. Rail) access from all one Greater London. Mail Order: 64 GOLDERS MANOR DRIVE, LONDON N.W.11. ALL PRICES INCLUDE VAT AT 15% 282 TELEVISION APRIL 1983

5 MULTITESTERS 30,000 any Including rest leads and case AC volts ,000 OC volts OC current:- 0.56ua 0-5ma-50ma 0-12arnps Resistance:- 0-6K ohms -10K ohms-6meg ohms- 6Onteg ohms Decibels- -20db to Mrs 56db. Shon lest:- Internal burden. Dims a 50mm 0/ OUR PRICE ONLY Amp SILICON RECTIFIERS Was Type sends SERIES 1, unco you snom VETS ALL NOW arms - NO &Ns Mn ion MOO - wont dog* ORDER NO S476 Silicon General Purpose NM T1111% Case/ Lock IA leads - carpi CV7644 Sender to BC107- /789 ALL NEW. VCE TOr IC500mA Nle off 100 orl 500 off 1000 on PRICE C Srlicon Genera Purpose PNP Translators ro-s Cue Lock Id Kees coded CV9507 seretar 2TiWOSA to BEX30 VC 60 IC 600dA Mn Hie 50 All NEW 50 on 100 oil 500 oil 1000 on PRICE Order as Cv9507 BI-PAK'S OPTO 83 SPECIAL A selection of large 6 Small size LED's in Red, Green, Yellow and Clear, plus shaped devices of different types. 7 Segment displays, photo transistors, emitters and detectors. Types like MEL11, FPT100 etc. Plus Cadmium Cell ORP12 and gems. photo transistor OCP71. 0/NO SX57A Pawed Normal Riled Om Wee MINIATURE TOOLS FOR HOBBYISTS Mrlelun round nose We Mem revemee hendaes HdrirCh loom IAA. No YD43 Holmium mime no *mien Mfg nom ohms mewed boodles Servich length Order No Y041 Minimum Mind rap piers Fondles 5VA100 length Oder No0040 leimerine end (move 11mn00 molt Order Na 0040 ohers woe SO Sef,alinl evsviered trendies 5miti length Order No TO47 MI with ieselated beadles insuieren hanehrs Silicon NPN'L'TypeTronsftors TO -T/ Mastic centre collider Like 8C18/L - 163E - 184L VC80 45 VCEO 30 IC200mA Hie ) neon DRIVER ALL perfect devices - encoded ORDER AS SX183L 50 on 100 of 500 off 1000 off PNP SILICON TRANS, TOR : Similar ZT E -Line VCEO 40 VON 35 k 300rnA lee Brand New - Uncoded - Pelee Devices 50 oft WO oh 500 ON 1000 ON f n. 4.PN A moot AtterArreer Ulf OM mewl M NI or imams Drool Mope ernince Order No IS -I lie Male Inini F5.2 two ppm no male. IIRIODRIVER fort long screwthrrer *me swam keeled gee on end to bold wirmis In mow w11e memo ma raw mitm omm Order No 51)-1 Fler pas Irmo 50.2 from poen 000 NR 555b MESIIIISEVE seats OF 11111WEOSE DAUM Combined... simmer Met mom Ind 25 mm nrmna t0, unnome Onlo No*02 Our ax once lei toe IRONI DIGITAL VOLT METER MODULE 3 rt 7 segment displays Basic Circuit 0-7v± instructions provided to emend voltage ft NO current ranges Operating voltage 9-12v SIREN Fled Oahu Par miff whirmidar Typ. Power Consumption 50mA ORh rn Eenis go Dolma.4011 rfnif. nl nevem oxen 100 mi. or, ninvinr Clem - 911mon Itha went WW1 POIAef 12 v r ' i- SEMICONDUCTORS FROM AROUND THE WORLD 100 AMacs. CoIlecI tciosnboolot riannsiicstaonisd Lineal plus which are current everyday usable devices tor 4 -o or %Fr Guaranteed Value over E10 at Normal Retail Price iruescotipf Rectifiers Bridgesall inodfges SCRs. s turyepv Order No SX56 OA RUT DRIVER SET Set of 5 BA spanner shahs plus universal handle in rcll-up wallet Sues ELA Order no 1192 E2.75 se MOM SCREWDRIVER Prrin Wade order no N each E1/21n blade order no IISO each Satisfaction or your money back has always been BI-PAK s GUARANTEE and it still is All these Sale items are in stock) in quantity and we will despatch the same day as your order is received IC SOCKETS The lowest price over. The more you buy the cheaper they come, Pin 10 oh 50 oh 100 off 115, eras ruse IV dr. so, LOPS ease II Nn 1160 E VOLTAGE REGULATORS Positive + Pleptive + T Sep SS, Sep SSp Sip SSe :824 - Sip SS, MW398 Universal NI -Cad battery charger. All plastic case with eh up IKE Charge/Test switch LEO indicators at each of the tone charging points Charges - POWS,' - PP319,1) Y AC U V Millim) Dims V "C") x 50mm,U2 t1 51#11 RO.1111 POWER SUPPLY OUR PRICE es.55 Power supply Ms directly into 13 amp socket Fused tor safety Polarity reversing socket Voltage switch Lead with multi plug Input - 240V AC 50HZ Output V DC Rating ma MW88 ig Money/ 1st can say& yvktkoft BI-PAK'S REVOLUTIONARY DYNAMIC "LOPT" TESTER Immediately tells the condition of a suspect LOPT without desoldering or removal. Guaranteed correct analysis in seconds saving you EEE's in Service Engineers TIME/ * Invaluable to all T.V. Engineers and unlike anything before. * Small, compact maim operated size: 10 x 7.5 x 4cms. * The D.T.T. is loiladivelly coupled by two loose turns of the toot Mod mod Me yoke or over the overwind on the saw* Nos wort transformer las illustrated). * The DWANE Tenn will give a positive rapid test by Otis dm sweewind if the transformer is sound. If ins faulty Ikea 1e E.H.T. will be given oft and the parishioner can be easily disconnected and replaced with confidence in only minutes. * Designed bye T.V. Engineer and is wholly British Made. Comes complete with instructions. Fully guaranteed. * 10 -day satisfaction money -back guarantee BI -PAX will refund your cash in full should you not be completely satisfied and return the unit within 10 days of purchase. immediate despatch - Ring Cardholder Hotline for same day despatch or send cash, cheque, P.O.'s etc. to: KNI,I,1 offlo Pd.., fo Dept Il Hi PAM Pfl F;(1% b VArAill Ill PIS SHOP Al ; HALDOCN 01 WARE PERTS ARMS CASH livith ORDER SAME DAY DESPATCH ACCESS AFICLAYCARD Al till ACCEPTED III ;2 GINO.18/i /Mk '-'.;.). ADD 10- VA1 AND Si,/ "ill OPCIER P AND PAT:10PC TELEVISION APRIL

6 .. P V Just MI. TUBES phone your order through, we Buy with Telephone: Accrington (0254) Accrington (0254) iall ti,,,,,wt. mew. do the rest 38A WATER STREET, ACCRINGTON, LANCS BB5 6PX. TRADE COUNTER OPEN MON-FRI 9 a.m.-5 p.m. SAT 9.30 a.m.-5 p.m. INTEGRATED CIRCUITS AN AN AN CA CA CA CA LA41131 P 321 LA LA LA LA LC C7120 5/7 LC LM1303N 2.63 HA MC MC131DP 1E0 MC MC1351P 1.50 MC1330P 93 MC MC MC MC MC1358P 1.50 MC1495L 3.00 MC MC14049U0 43 M1231/RETTA MC ML M ML ML M1239 2,50 ML ML ML ML MRF MRF MSN PLLO2AG 969 MS1513L 210 MS1515L 3.71 SAS SAS560S 130 SAS SAS SAS SAS SL901B 5.18 SL SL SL SL SN76003N 2.49 =SN76013N SN76023N 220 SN76110N 1.15 SN76115N 227 SN76131N 2.00 SN76226(DN 200 SN76227N 1.18 SN76530P N SN76533N 130 SN76033N 165 SN76544N 235 SN76650N 105 SN76660N 80 SN76666N 80 STK SW TA7050P 95 TA7051p 95 TA7074P 100 TA7108P 3.43 TA7120P 243 TA7129AP 3.76 TA7130P 1.93 TA7141P 95 TA7193P 5.67 TA7171P 1.85 TA7172P 135 TA7173P 1.85 TA7176P 2.50 TA7193P 5.67 TA TA7204P 3.77 TA7205AP 3.72 TA7208P 3.40 TA7210P TA7227P 5.33 TA7202P 528 TA7310P 2.78 TA7609P 439 TA7611AP 2.92 TAA TAA TAA TAA350A 60 1AA TAA TAA (1 300 TAA8400S TAA TAA TBA120A 70 TBA120S 70 TBA120SA 70 TRA120AS 137 TBA TBA TBAI2OU 115 TBA TBA TBA440N ITBA TBA44OP 2.50 TBA4801(1) 1.50 TBA TBA520Q 1.68 TBA TBA TBA TBA TBA TBA TBA641BX TBA TBA TBA ,10 TBA810AS 135 TBA TBA TBA TBA T84950(2X) 2.40 TBA TBA TBA TCA TCA TCA270SQ 2.50 TCA TCA TCA TDA TDA TOA1003A 5.50 TDA1004A 2.95 TDA1006A 2.50 TDA TDA TDA TDA TDA TDA TDA1327 1,70 TDA TDA TDA TDA TDA TDA TDA TDA TDA TDA TDA UPC UPC1158H 78 UPC1163-H 9111 UPC1181H 1.12 UPC UPC1212C 1.34 UPC1230H 3.95 UPC1378H 4.49 UPC UPC566H 2.95 UPC575C UPC1025H 2.95 UPC1182H 2.95 UPC1156H 426 0PC1350C 4.15 UPC1185H 326 TDA TDA TDA TDA TDA TDA VOLTAGE REG. I.C. TDA257I 2.56 TDA TDA TDA TDA TDA TDA TDA2680A 3.40 TDA A M L L L L L L LA SUPPLIERS T.T.L 741.S SERIES 74LS LS S LS LS LS32 20 '4000 B' SERIES QMOS 4001E B B B B B B B B OF TELEVISION COMPONENTS LS LS LS S LS LS LS S B B B B U E B B S S V 74LS S S LS LS LS LS LS LS LS S B B B B n 4081B B LS LS S LS LS LS LS194A 69 74LS LS LS M M LS S S257 M LS LS S LS LS LS LS LS LS S ee 74LS B B B B B B THERM STORS SEMICONDUCTORS BC BC BF EIFX TIP31C 56 2SC1172Y mama VA DEC Dual AC BC107A 79 BC BCX32 30 BD BF BFX A TIP32C Mhz 130 va Posistor 128 AC BC107B 20 BC182LB 10 8C BD E BFYSO 30 BU208A 1.65 TIP SC1173Y 131Mhz 130 VA GEC Dual BC183L 13 BC E BFY /02 T1P ,692Mhz 500 VA ICK BC BC557 8 BD E BFY TIP41C 46 2SC AC127 AC A BC108 BC108A n 20 AC128K 40 BC BC BC558 9 BD E BFY TIP42C 17 25C NEW VALVES EY500A 1.50 PFL203 I26 AC BC108C 20 BC BCX E BU TIP C1449 1E7 30FL EZ80/1 95 PL AC141K 39 8C109 A BC CY72 13 BD BF BU TIP SC GY501 1,45 PL81 91 AC142K 38 8C BC EIDSP 52 8E BR BU TIP SC /7 M GZ34 AC BC109C 20 BC212L 13 BD116A 65 BD BF256LC 211 BRC BUM 294 TIP SC ECC KT PL84 84 AC176K 32 BC BC P 79 BD E BRX TIS SC ECC82 M KT PL AC BC BC213L BF257 A BRY TV106/02 2SC ECC PC92 93 P AC BC BC BD BF BRY56 57 E SC ECC84 80 PC97 1E5 P AC187K 38 BC C BD F BR MJE340 El 2N SC ECC PCC85 85 P1509/ AC BC BC E BRC MJ3000 IA 2N SC ECC PCC P1E102/S 3.50 AC1813K 39 6C BC BD BF BSV N SC ECF80 80 PCF PY BC BC BD BD696A F BSW67 M ECF82 A PCF PY500A 136 AD BC BC BD BF SW AD BC BC BD BF BT100/02 92 SW153A 2N /2 BC BC238A/ BDX BF BT101 IA N BC148 9 B/C 8 B F E /500R / BC5481 BC BF E N AF BC BC252A BF BF BT MJE340 A 2N37C6 10 AF BC BC252B 12 BD BF BF N3708 V AF BC BC261A BF E N AF BC BC261B in 8E E /500R R2008B 193 2N AF BC BC262A )160 V 6E ) R N AF125 A BC161 n BC E E BT R N AF BC BD E BT N AF127 3 BC BC E ) R AF139 A BC171A 10 8C BD E E / AF BC171B 10 BC E179 3 BFR R N AF BC BUM 25 B E BFR BU R N L BC172B 10 BC E E742 A BU R A AU BC172C 10 BC BF E143 A RCA SC AU BC173C 12 BC BF BFW RCA C AU BC174A/B BC BD BF BFX29 40 BU TIP29C 43 2SCB43A AU BC E BFX TIP30A BC BC BC E BFX85 30 BU TIP30C 43 2SC REBUILT COLOUR TUBES ALL AVAILABLE IX -STOCK ON GLASS FOR GLASS EXCHANGE BASIS FROM TRADE COUNTER 17" A44/271X 3 2 NB Mail Order 18" A47/343X (Stnd Focus) supplies Mabee. 30,151 18" A47/342)( (Low Focus) 30A We will send 12' + 'CARBON RESISTOB )W 3R3-8M2 20 phi OW 3R3-8M W M 36 per 2W 10R -10M 62 type 14" portable tor E5 WIREWOUND RESISTORS* carriage. (Preferred Values)* 19' 449/120X 3080 For 20" + 24" Mono 4W 16-10K each 2D" A51/110X 30--M and all Colour tubes 7W 1R -22K 21p each 22" A56/ please ring for 11W 16-22K 22' A55/14X p each 17W 1R -22K 28p each 25" 863/ delivery service and 26" 866/ quotes for the 26" A67/120X 3400 MULLARD COLOUREX/ return of old glass. 22" A56/ ) Certain tube types NEW LIFE 26" A66/140X " A51/161X " A56/510X 5010 P.I.L. TUBES- we can rebuild your own glass - please ring for quotes, quotes on next daylg LLIDOLL6 DIL to DIL 8 way way...,41 16 way 34_,. 18 way 0 20 way way way 38 Lill to (MIL 14 way way w ay 37 QUIL to DUD 14 way way ' CERAMIC FILTER 6Mhz Mhz SPECIFIC COMPONENTS SOLDERING EQUIPMENT PHILIP'S Solder Iron Stands 2.50 G8 Knobs S 50 WELLER Iron 15W 438 G11 EHT Final An- WELLER Iron 25W 438 ode Lead 150 WELLER 3/16" Single Flat E.W. Correction Coil G Tip 51 Transductor MIN Soldering Iron 5A THORN WELLER Heat Gun Speakers Sm 4.10 IPairl Tips for Gun ANTEX Soldering Iron 25W520 ECH PCF P9800/1 69 ECH PCF UCF80 67 ECL80 84 PCF UCH ECL PCF UCL ECL PCF UCL EF80 95 PCF UL EF PCH F23 85 EF PCL UY EF PCL PL802T COO EH PC185/805 A E PCL EL PC W4A 180 E EY86/7 93 P LINE OUTPUT TRANS. R.B.M. T DEC R.B.M. A774 Mono 1134 GEC M GEC R.B.M.Z718 22" ITT CVC PHILIPS ITT CVC 25/30/ PHILIPS 210/ ITT CVC Mono THORN 3300 EHT 6.33 PHILIPS GO 8.75 THORN 3000 SCAN 610 PHILIPS G9 325 THORN PHILIPS THORN PYE 691/ THORN PIE 697 (Printed) 1450 THORN 3000/ PYE 713/ ains P9E THORN PYE A THORN DECCA 813/ THORN DECCA 17M 900 THORN 7X DECCA THORN DECCA PHILIPS KT Frame Hold 390K 32 ANTEX ST4 Stands 230 MICRO COMPUTERS 1500 Line Hold ANTEX elements 1.65 Spectrum 16k (incl. VAT) 1500 Contrast Solder Remover Sucker 650 oric 49k (incl. VATI Focus Control Thorn/GEC 123 Solda Mop 72 Jupiter Ace (Forth) Imcl.VATI can be supplied 18" A47/343X )31 Mains Filter Choke Reel Solder without a glass 19" A49/120X sae 8510 Focus Unit Lynn lincl. VATI DIY Type Solder,4.,.3 Texas (incl. VAT) exchange with a 20" A51/110X 53,00 7X10 Focus Controls9D Solder "4. Commodore lincl VAT) basic glass charge 22" A56/120X 4300 incurred. DECCA 100 Atari k lincl VAT) 25" A63/200X 5510 RECTIFIER STICKS Bridge Transformer 97 Please ask -we will 26" A66/120X /11 74 TV Series Width Control 50 Full rante of software/ try to help. 26" A67/120X /18 81 TWO 95 BR9 Nodulohm 60 peripherals, NEW MONO TUBES Height Control 2M2 25 Aerials, coax cables, splitter Visit our showroom MULLARD A31/ r 12" VEGA A61/120WR 24" MULLARD A.34/ " VEGA 2" 90 (Japanese Types) VEGA A50/120WR 20" CMEI " Mono) RFD 1.20 Focus Control 220Ring PYE 731 Mains Fitter Choke 650 combiners, etc. and a lull range of aerial equipment available from trade counter. for availability. These prices include VAT 284 TELEVISION APRIL 1983

7 P. V. TUBES REPLACEMENT ELECTROLYTM ELECTRONIC TUNERS AND ASSEMBLIES PYE /2011/100/32) 2.12 Mullard ELC1043/ PHILIPS /400/ Mullard ELC1043/ DECCA /400/350V P/B DECCA/GEC/ITT 693 DECCA 80 14/3/350/ P/B DECCA/GEC/ITT 710 DECCA /250V) P/B PYE SOO DECCA C0/200/403/350V) it P/B PYE PHILIPS /300VI 221 PHILIPS G8 Tuner PHILIPS G /300V1 221 PHILIPS G8 Ass (Square/Early) PHILIPS /250VI 2.90 PHILIPS G8 Ass (Sloping/Latel PYE 691/7 1200/313/ PHILIPS G9 Tuner 10.50' PYE V PHILIPS Gll Tuner 900 RBM A /2500/30VI 116 PYE 697 Repair Kits 6.97 RBM A /300VI 13 ITT 6 way P/B with VCR 8.90 RBM Z /3/0/350/ ITT/PYE/GEC 7 Button P/B RR1 T20A 1220/400VI 2.3 GEC way P/B 7.98 ITT CVCS/9 (200/203/75/25) 217 U321 UHF Tuner 7.50 ITT CVC / THORN 6903 SELECTOR GEC /250V (HMV Model 2725/6 way round button) 7.50 GEC /2E00/35V) 1,19 THORN 9003 SELECTOR 1110 GEC 2040 (300/303/150/100/ U THORN 3510 (000/40V) 30 HITACHI 0 way Chan. Selector (Also Rank A823I THORN 950 (19/300/100/16/275V) THORN W100/1011/100/150/320Vi 2.79 RR1 T20A 6 way Chan. Selector 9.75 THORN /150/1M/300V) 201 RRI 720/22/ THORN /300VI 31 PHILIPS 8 way TIP Switch Unit (suitable for all 6111 THORN / /25V) THORN /100/100/400/350V1 216 KT3 PHILIPS THORN /63VI 65 KT30 PHILIPS 1030 THORN 3500 (103,70V) THORN 890/ /2503/63V THORN 3013/ P/C 25V) 1.3 THORN 8030/8500 (700/250V) 231 THORN 8000/ /35051) 2.% THORN %CO 1400/40ovl 3% GEC 129/29/150/ CAPACITORS AXIAL Volts Mfd Price V V V : V V I D V I MIXED DIELECTRIC CAPS Volts D.C mF mov 022mF 600V 0.1mF 1030V 0.0ImF 0.047mF 0.033mF 0.1mF OnmF 0.47mF 1250V 0.1mF 0.91mF 1500V mF mF 0.022mF 0 (333mF 0.005mF 2000V mF A se 59 es CERAMIC CAPACITORS 63V A range of pref values each 22pF479pr 6p PHILIPS /63V 1.25 CONVERGENCE PRE-SETS 3 Watt complete with knob 5RO6RB-10R 15R 20R R -203R 59R 60 METRIC CONVERGENCE POTS PHILIPS GE1 5R -10R -20R -50R 35 NEW PRODUCTS ASSTD. Philips RGB 10G diodes 50 OR 39 3W resistors so Switch 2E0 Focus Unit 790 Focus Unit 230 Focus Unit 230 Philips Clock Radios IAS390) 2139 Fluorescent Torch 5 pin -5 pin Audio Leads Travel Plugs Electrical Circuit Testers Video Head Care Kit L5 r x 3s 'Speaker 15R Ayr Teletext Adaptor Battery Chargers Universal 6.50 se Gen. Purpose Thristors THY15/ (many applications) THY15/85 Dudes SKE 4W2/ SKE 5F/3/ SKE 46/2/06 91 Video Heads VHS ("Universal") Diodes Y YB ReFAN1500 RX14 -SP11/HP11 NN1400 RX20 - SP2'HP1'NN1300 RX22 - PP3 NNI604 VIDEO/AUDIO VHS E30 VHS E60 Scotch E120 Video Tape Scotch E180 Video Tape BETA L503 BETA L750 PHILIPS VCC 240 PHILIPS VCC 360 PHILIPS VCC 480 Video Cassette Cases Green/Brownl Scotch Audio Tape C90 Ferric C90 Super Ferric SWITCHES 4A Double Pole On/Off Switch General Purpose Push/Push Philips 58 Push On/Off Switch 4A Double Pole Rotary On/Off Al Beam Switch (THORN Al Controls 5m (THORN GEC 2110 Al Control 1M5 IRed, Blue GEC 2040 On/Off Switch On/Off Switch G11/612 On/Off Switch GEC/TCE TX9/ IRed/Blue/ PANELS + UNITS AFC UNIT PHILIPS G8 082 IF GAIN MODULE (Pya/Philips) 900 CDA PANEL (Pye/Invicta/Ecko/Dynatronl 2020 REAR CONVERGENCE PANEL (Phdips GB) n Green) 58 SUNDRY TUNER ACCESS, RANK Tuner P B ;" 2, (yes we have some, I HANK Drive Cams GEC 2110 Tuner Neons SUNDRIES Delay Lines DL DL DL EHT Final Anode Cap 53 EHT Cable mtr. 6.3V CRT Boost Trans A Plug Top box Adhesive Moulded Plastic Hex. 6mm Trim Tools 10 Double End 4mm(Omm Trim Tools 20 Focus Rod 1.25 Focus Holder 2.00 Keynector Safe Block (mains) 5.50 Cassette Drive Belts per pack of mm mm mm mm mm 1.90 Torch (handy for tool box) 42 I.C. Inserter 1.18 SM Neon Screwdriver 40 DIN Plugs 3 pin 22 4 pin ` 5 pin 20 Stnd 5 pin 20 Phono Plugs 12 Car Aerial Plug mm Jack Plug mm Jack Plug 14 Stnd. Jack Plug 20 Stereo Jack Plug 36 5A Connector Block 112) 40 Fuse Wire 5A -15A -30A 5 Battery Plug Thorn TV's 28 Gen. Purpose Power Supply 3.25 W 200ma 12V 200ma Mains Connector 4 way I3A SOO TEST EQUIPMENT Portable sc lloscope Probes x CRT Tester/Rejuvenator KHP30 Measuring Probe 13 okvi EHT RF Signal Iniector 4.00 Avo 8 Test Lead Set 420 Degaussing Coil (stick typel 1550 Degaussing Coil )disc type) Universal Battery Charger 750 SERVICE AIDS SERVISOL Freeze It 96 SUPER SERVISOL 3 SERVISOL Foam Cleanser 84 SERVISOL Plastics Seal 138 SERVISOL Silicone Grease 100 SERVISOL Tubes Silicone Grease 160 SERVISOL Aero Klene 78 SERVISOL Aero Duster 94 SERVISOL Excel Polish 76 Penetrating Fluid 70 Fire Extinguisher 640G 290 Heat Sink Compound Silicone Rubber Tube Solda Mop standard reel 72 Super FUSES ' Per 1... QUICK BLOW type ituma 250ma-59rna-750ma IA 1 5A-2A-2.5A3A-5A 14- ANT1SURBE 250ma 50Dma 603ma 630ma. 750ma. 850ma. 1A, 125A I.5A 2A 1 5A 3A. 5A 20mm x 5mm ANTISURGE 80ma 100ma 160ma, 200ma 3I5ma 500ma 630ma 800ma IA 125A 16A 2A. 25A 3.15A 20mm x 5mm QUICK BLOW 100ma. 250ma, 50Ckna. 630ma, 800ma IA. 1.25A 1.6A. 2A 25A 3 15A SA 1" MAINS 2A, 311, 5A. 10A, I34 AERIAL ACCESS. Ae7ral.ea 2m Mang Splitter 120 Surface Mount. Splitter 1.70 Surface Mount Outlets80 Cable Clips per Coax Plugs per P.V.C. Tape 35 F.M. Plugs 25 PL259 Plugs 40 Line Connectors 35 Reducers for P T V Filter 50db Refection 17mhz 2.10 Attenuators 6db. 12db 18db ISO Olympic II Set Top Aerial 220 Pack of so M.H.A.U.P. the pa, 1600 Aerial Isolator Ka m Fly Lead 120 2m Fly Lead 90 ANTIFERENCE CS280/SP Comb/Splitter Indoor Splitter 1.91 COB I 1 Single Outlet 78 TRR/VSP Transformer R 2.25 Super Set Top Aerial 6.80 Caratenna 7.60 XG8 High Gain Aerial A -B -CD or W B NB A full range of aerials and accessories available from trade counter MINIATURE SKELETON PRESET POTS Horizonte' or Vertical 100R 220R K0-2K K K470K-1M0 each STANDARD SKELETON PRESET POTS Horizontal or Vertical 100R 220R -470R -1K0-2K2-4K7-10K 22K47K 103K 220K -470K M) each SLIDER POTENTIOMETERS Lin or Log 47OR 65p 2K2 4K7 65p 47K 1K 65p 1013K 10K 65p 470K MIDGET CONTROLS Insulated Spindle Length 44mm Log or Lin Without Switch 5K-10K-25K-50K100K250K-59K 1M With D.P.S.T. Switch Log: 5K -10K -25K -50K -100K 250K 500K 1M 2M THERMAL CUT OUT THORN A Metal 110 THORN Plastic 1.60 GEC 2040 Metal 2.50 MULTITURN 65p 65p 65p 65p 39p 81p 100K 55 GEC TCE 55 PHILIPS GO DECCA. RANK 55 THICK FILM RESISTQR NETWORK THORN pin connection) 1.93 PYE pin connection) 220 THORN 9000 (Circuit Ref. R704/ EAGLE PRODUCTS Please send large S A E for full EAGLE Catalogue DF615 Full Range Speaker 6; 8.% Multentaires KEW 7N 2000 clay 525 KEW EM5 5,001 am, 9.95 EMIO opv EM opv 13.3 EM50 50,000 opv EMC321 Carrying Case for above 225 Digital Meter TS MM P V MM P V MM P V MM P V MM P V TL64 Test Leads 1/3 Case for MM Station Intercom 6.96 PATA BOOKS (No VAT) Transistor Equivalent TVT 80 A-2 only 3.75 TVT 80 2N/2S series oniy 400 TVT 80/80 Al and 2N/2S together 7 50 LIN IC Books LIN LIN Please ensure that you order out of the latest magazine to avoid missing some inevitable price changes. DCIApSCACCEITRrRSIC 8kv (12kV VVIag) 39pF each 1F 1F pF 2500 ELECTROLUBE PRODUCTS Electroluhe Adhesive 62 ElectrOMech lubricant 1.49 Elect cleaning solvent 162 Freezer 1e9 Foam cleanser 1.12 Heal transfer compound 1.14 Silicone compound 1.94 Special contact fluid isnorkell 320 Permagard 1.52 Elec. meth lubricant pen 71 LABS EAR CM7061 Power Unit I2V CM7062 Reg Power Unit I CM7060 MHA 10db 12V W/B 894 CM7065 VHF/AHF MHA W13 12V 1301 CM7067 UHF 121/ MHA ISpecify A -B or C/ CM7068 UHF 12V MHA High Gain (Specify 118 or C CM /053 Behind Set UHF Amp (Mains) CM /054 Behind Set UHF Amp (Battery e g Caraorco 945 CM7043 Second Set Amp UHF 1100 CM7093 Behind Set UHF Amp 3 Sets 1386 CM7068 Dist Amp VHF/UHF 17db, output 12V20.10 CM7073 VHF 'UHF 8r1 Dist Amp 3921 CM mhz CB Suppress 3.60 CM6011 Outdoor Sputter 12 wayl W/B 7.10 CM9003 Flush Single Outlet 134 C39010 Flash Twin Outlet 1.78 CM9034 UHF Group Fitters with DC Through Pass (state A/B/COQ I 6.90 CM Way Passive Splitter CM7042 TV Games Combin 2.56 CM9009 Flush TV/FM Outlet 2.77 CM7069 Tn Star Amplified Set Top Aerial W/B CM7090 Amplified Caravan Aerial 12V DC W/B CM6038 UHF/VHF 625 Pattern Gen 9605 CM6052 UHF/VHF PAL Colour Bar Gen RECTIFIER TRAYS THORN 950 Mk II 425 THORN Stick 425 THORN Stick 4.9 THORN Stick 529 THORN THORN THORN THORN THORN 8500/ THORN DECCA 17313/ DECCA 1910/2213 Bradford 5.92 DECCA DECCA E DECCA UNIVERSAL ITT or REMO 600 GEC GEC AX) 6.50 GEC 2040/ GEC 2110 Pre Jan ' GEC 2110 Post Jan ' PHILIPS 68 Short Focus Lead 6.70 PHILIPS 613 Long Focus PHILIPS G9 637 PYE 691/3/ PYE 713/4 Lead 7.00 PYE 731/ R.B.M. A823 (plug in I AV 7.40 R.B.M.A RBM. T KORTING (similar to Siemens TVK11 ITT KB CVCS/ ITT KB CVC20/25/30 (Mullardi 8.60 RRI T MAINS DROPPERS DECCA DECCA 2R5 85 DECCA 27R/42R 1.40 DECCA 56R/6R R.B.M. A823 3 R.B.M GEC 2003/ GEC PYE 713/15 3R5/15/45R 120 PYE 731 3R/23W 1.98 PYE 725/31 3RO/56R/27R 184 PYE R/27R ISO PHILIPS 210/ R/125R/2k PHILIPS 210/5051 '118FP148R 93 PHILIPS 58/ R Section 50 PHILIPS 58/5083 2R2/68R RANK 56R -68R A823 THORN 1400 THORN 1500 THORN 1600 THORN 3030/3500 THORN 8000 THORN ZENER DIODES /85 (13W1 20 6V2-7V5.8V2-91/1-10V-11V- 121/-13V.15V etc up to 75V 11192La AAII9 9 BA BA BA BA154 6 BA BA BA BAX13 4 BAX16 8 BBIO5B 30 BB105G 30 BY BY BY BY BY BY BY / / BY BY210/600 BY210/ BY BY227 3 BY BY299 Z2 BYXIO 20 BYX36/10 30 BYX36/600 BYX55/ BYX7I/ OA N914 N4001 N4002 N4033 N4C04 N4005 N N N4148 N4448 N5401 N5402 N5033 N5404 N5405 N N N TT44 4 TT Y969 (30V Thorn 3500, 89 BIY15-24R 118 BIY15-12R 1.18 BIY V 1.18 BZ M1N1 10 2V7 3V.3V3-3V6-3V9-4V3-4W.5V etc up to 24V HOW TO ORDER ADO 65p per order for Post and Packing (UK) (Export orders will be charged at cost I THEN ADD 1% VAT TO TOTAL COST. Orders which contain aerosols or degaussing coils are very heavy- please add extra per can/coil. First Class Mail is used whenever possible. All enquiries SAE please. VAT invoice on request SEE SPECIAL NOTE RE MAIL ORDER TUBE COSTS. Goods are despatched on the day we receive your order If for any reason we are out of stock we will try to inform you as quickly as possible We try ow hest to give a speedy. fair and efficient service. As our regular customers know orders telephoned n hefore 4 p.m win he despatched the same day Give us a hog - we'll give you service Please ask if what you need is not listed -- we will try to help For test equipment etc. Please allow an extra 50P per parcel Prces are sub(ect to change without notice TELEVISION APRIL

8 , -4- _ B.K..e il ELECTRONICS e. it 1 I 114 +J1. I - INCREASE YOUR PROFITS - IMPROVE YOUR SERVICE WITH RELIABLE COST EFFECTIVE TEST EQUIPMENT t SAFGAN DT -420 DUAL TRACE SCOPE 20MHz BANDWIDTH SPECIRCATION * CH1, CH2: 5mv/div-20v/div 0 * Time Base: 1 sec/div-10ons/div * XY Facility: Matched XY inputs * Trigger: Level control, -± slope selection :,_u,,,,a.6:dnuttrr:nl, * TV triggering *CAL output 1V 1KHz * Graticule blue ruled 8 x 10 div (4" CRT). Very Sharp Trace. * Size: H215mm, W165mm, D280mm * Weight: 4kgs * Supply: V, 40-60Hz PRICE f29.85 VAT Probes as Thandar below. BRITISH MADE - RELIABLE - 18 MONTH GUARANTEE LEADER LCT-910A C.R.T. TESTER -REJUVENATOR Our top selling instrument is designed to readily test the various characterisrejuvenation of both colour and tics and B/W c.s.re. * Tests for shorts and leakage between electrodes. * Tests cathode emission characterischecks condition of tics. * Separately guns. * Removal of shorts and leakage beelectrodes. tween * Checks heater warm-up characterisof low tics. * Rejuvenation emission cathodes with automatic timing. * Super rejuvenation with manual conwith tube base trol. * Complete adaptors. Size: H 230mm W 330mm 0 120mm. i Q 6 o -0 Ir.- PRICE VAT THE VERY LATEST SC110A LOW POWER, FULLY PORTABLE OSCILLOSCOPE. The new Thandar SC110A represents a break -through in oscilloscope development. The SC110A is ONLY TWO INCHES thick and weighs under two pounds, yet retains the standard features and controls of a bench oscilloscope. FITS IN A BRIEFCASE, 0 D,.j.' L) r o i GOLD MEDAL winner of the B.R.N.O. EXHIBITION, the largest Trade Fair held in Eastern Europe. Full Sized Performance 10 MHz bandwidth. 10 mv per division sensitivity. Full trigger facilities are provided including TV frame, or TV filtering. Runs on 4 to 10V DC via disposable batteries, re -chargeable cells, or AC adaptor. Size 255mm. 148rnm. 50mm. 'Scope VAT. Carry Case V.A.T. x 1 Probe V.A.T. BRITISH x 10 Probe f C1.20 V.A.T. FULLY MADE x 1/x 10 Switched Probe VAT GUARANTEED Rechargeable Batteries V.A.T. AC Adaptor V.A.T. (Overseas purchasers please state voltage.) LEADER HIGH VOLTAGE METER EHT PROBE `''...!,... Measures up to ' ' 4 0`,,,, K.V. D.C. with "-- 411# SAFETY BUILT IN PRICE METER VAT -..,... - ALSO AVAILABLE Analogue Multimeters Digital Multimeters Oscilloscopes Signal Generators Digital Frequency Meters Pattern Generators CRT Tester/Rejuvenator T.V. Field Strength Meter LARGE S.A.E. FOR COMPLETE LIST. U.K. Post Paid. Export orders welcome, please deduct V.A.T. and include an additional 5.00 for Overseas carriage. Mail Order only. Callers by appointment. Barclaycard/Access orders welcome, or Cheque, Bank Draft etc., with order please. Large S.A.E. for technical leaflets of complete range. Delivery normally within 7 days. B. K. ELECTRONICS, Dept. 'T', 37 Whitehouse Meadows, Eastwood, Leigh -on -Sea, Essex SS9 5TY. Tel: (0702) _ LOPC I AR111) or._. UNIVERSAL PROGRAMME SELECTOR FOR VARICAP TUNING 6 way interlocked d. p. switch 100 K tuning potentiometers Top quality through hole plated pcb Dimensions: 5' by 21" by 1" Ideal for replacement when original parts are obsolete or unobtainable Template guide supplied for drilling of your own fascia design Range of precut and drilled fascia/mounting kits for selected TV chassis enabling our unit to be fitted without further cutting drilling or modification All orders despatched same day UK Regd. Design No DIRECT REPLACEMENT FASCIA/MOUNTING KITS Type Replaces 7 piano -key unit as fitted to Decca/Telefunken 30 and 80 chassis Type 30-C Replaces 7 piano -key unit as fitted to Decca console using long perspex Illuminated control panel Type 100 Replaces 8 position touch tune selector (AEG SAS 660 SAS 670) as used in Decca/Telefunken 100 chassis Type CVC8-9 Replaces 5 rectangular push button plus thumbwheel as used in ITT SELECTOR 11 + VAT FASCIA/MOUNTING KITS (each) 2 + VAT ALDERSON-JAMES LTD 160 KINGS ROAD HARROGATE N. YORKS TEL: HARROGATE (0423) HG1 5JG N.J. ELECTRONICS UNITS 82/83/84 STORFORTH LANE TDG. EST. HASLAND CHESTERFIELD, DERBYSHIRE S4I OSN. TEL CHESTERFIELD PUSH BUTTON UNITS EHT TRAYS DECCA 30 6 button 7.96 DECCA GEC DECCA GEC button SEIMENS UNIVERSAL 6.30 GEC 2136/ GEC 20AX 6.70 ITT CVC GRUNDIG ITT CVC KORTING 7.22 G8 SQUARE (early) PHILIPS KT G8 SLOPING (later) PHILIPS PYE button 9.15 PHILIPS PYE CHELSEA ITT CVC RRI button E8.74 ITT CVC RRI button 9.45 RRI button 9.90 TELPRO 4 button 8.75 ICs TDA LOTXs TDA THORN 1590/ TDA THORN TDA THORN 1690/ TDA RRI T20/ TDA RRI TDA PHILIPS G TDA PHILIPS G TDA PHILIPS TDA PHILIPS G TDA PHILIPS K TDA ITT CVC30/ MC11358P 1.40 ITT CVC MC TBA ADD 65 PENCE POSTAGE + 15% VAT TO ALL ORDERS. (See CONTRAST U.K. advertisement in this copy, all your component, panel and TV needs under one roof). 286 TELEVISION APRIL 1983

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10 TRANSISTORS, ETC. Type Price (CI Type AC AC AC AC AC AC128K 0.55 AC AC141K 0.70 AC AC 1 42K 0.65 AC AC AC ACI 53K 0.52 ACI AC AC AC AC ACI 87K 0.65 AC AC188K 0.81 ACI 93K 0.70 AC194K 0.74 ACYI ACY ACY ACY ADI AD AD AD AD AD 1 61/ AD AF AF AF AF AF AF AF AF AF AF AF AF AF AF AF AFI AF AF AF AF AF AF279S 0.91 AL AL LINEAR IC's Type Price (Cl CA8100M 2.50 CA CA CA CA CA CA3028A 0.80 CA3028B 1.09 CA CA CA3065 1,74 CA CA3I FCH FCJ LM309K 1.98 LM380N LM1303N 1.03 MC1307P 1.82 MC MCI312P 2.34 MC1327P MC1330P 0.83 MC135OP 1.22 MC1351P 1.42 MC1352P 1.42 MC1357P 2.92 MC1358P MC1458G 1.43 MC1496L 1.15 MC3051P 0.58 MFC400B 0.86 MFC4060A 0.98 MFC MIC1P 1.10 ML231 3,57 ML NE NE566 SAAI SAA SAS SAS SC9503 P 1.40 SL432A 2.52 S L SL901E SL917B 6.50 SL918A 5.95 SN72440N 2,21 SN76003N 3.32 SN76013N 2.52 SN76023N 3,02 SN76023ND 2.52 SN76033N 3.32 Price fl AU AU AU I AU I C BC108* 0.15 BC109' 0.16 BC BCI BC BC BC BCI BC C125* 0.30 BC BC BC BC BC BC BC BC BC BC C1413. BC BC BC BC BC BC BC BC C BC C BC169C BC170' BC BC BC BC1744 & BC BC177' 0.20 BC BC179' 8C BC182L BC BC183L 0.14 BC184. BC184L BC BC BC Type Price (C) SN76023ND 1.40 SN SN76110N 1.20 SN76115N 1.62 SN76116N 1.78 SN76131N 2.10 SN76226N 2.60 SN70227N 1.61 SN76228N 1.80 SN76502N 1.92 SN76530P 0.97 SN76533N 1.38 SN76544N 1.85 SN76546N 1.85 SN76570N 1.81 SN76620AN 0.99 SN76650N 1.48 SN76660N 0.64 SN76666N 0.96 TA7073P 3.51 TAA263 TAA F TAA TAA350A 2.48 TAA370A 3.18 TAA TAA TAA TA4522 2,09 TAA TAA TAA TAA611A 1.87 TAA611B 2.85 TAA6214X TAA TAA TAA661A 2,39 TAA661B TAA TAA TAA86 I A 0.95 TAA930A 1.43 TAA TAA TAA TAD TBA S TBA I TBA TBA TBA TBA395* 2.58 TBA TBA Type Price(11 Type Price If) Type Price( f) BC BC BC204* 0.39 BC BC205* 0.39 B C BD BC206* 0.37 BC BD BC207* 0. BC BD BC BC BD BC209' 0.39 BC BC BC C BC BD C2121." C BD BC213' 0.16 BC BD BC BC BD BC BC BD5I BC BC BD C BC558' 0.16 BD BC237' C559' D C238* 0.15 BCY BD663BR 0.86 BC239' 0.22 BCY30A 1.08 BOX C BCY32A 2.95 BC BCY34A CD)Y) BC BCY BDY BC2614* 0.28 BD BDY BC2624* D BDY C BD EIF C Y 1.56 BF C BD BF BC BD BF BC BD E FIC BD BF BC BD BF BC E) BF137F C BD I F BC BD BF BC BD BF BC BD I F C BD BF BC307' ' 0.51 BF BC308' D BF BC309' 0.18 BD BF C BD F BC318' BF BC319' F C BD BF BC ,18 BD BF BC BD BF BC BD BF BC BD BF BC BD BF BC BD BF BC BD BF B C BD BF C F BC3484 & B BD F195' BD BF BD BF BC350' BF BC BF BC BF BC BD BF Alternative gain versions available on items marked.. Type Price le) TBA TBA TI TBA520 TBA530P TBA540* 2.88 TBA550. 3,13 TBA560C 3.18 TEI4570' 1.29 TBA TBA64 I 4.55 TBA6418X TBA TBA TBA700' TBA TBA TBA81OAS 2.00 TBA TBA TBA TBA990' TC TC TC TCA420A 2.10 TCA TCA640 TC TC TC4730 TC TC4750 2,53 TCA820 TDA TDA TDA TDA TDA TOA TDA TDA TDA ZN to series available. Full range of C Mos in stock. Indicates 0 version is also available. SPECIAL OFFER 25 AU110 for DIODES Type Price If) Type Price fl BY BY BY ,28 BY BY AAY BY Z BY BY BY AY BY BA BY BA BY BA BY BA BY BAIII 0.70 BY BA BYX BA BYX38/ BA BYX70/ BA BA IT BA IT BA MCR BA MR BA A A BAI A BA , BA A BA A BA A A BA A BA A BA TIL BA TIL BA TV N BAV N BAV N BAW N BAX BAXI BAX BAY N EI N N BB105G 0.30 N N BY S BY S ZENER DIODES 400mW plastic V 1/1.3W plastic V 1.5W flange V 2.5W plastic V 20W stud V 14p each 18p each f1.28 each 67p each 1.31 each Type Price If) BF BF224 & J 0.22 BF BF F BF BF F BF BF BF BF BF BF263 6F270 BF27 1 BF273 BF274 BF336 BF337 BF338 BF355 BF362 8F363 BF367 BF451 BF457 BF458 BF459 8F594 BF596 8F597 BFR39 BFR40 BFR41 BFR50 BFR52 BFR6I BFR62 BFR79 BFRBO BFR81 BFR88 BFT41 13F143 BFW11 BFW30 BFW59 BFV460 BFV490 BFX29 BFX84 B FY50 BFY51 B FY52 B FY53 8 FY90 BPX , VOW., etc. Type Price (f) E295ZZ / / E298CD /A E298ED /A258 /A260 /A262 /A265 /P288 E298ZZ / / E299DD/P116- P354 all 0.23 E299DH /P VA VA VA I 033/34/38/ 39/40/53 all 0.20 VA1055s/513s/ 66s/67s all 0.23 VA VA VAI VA1096/97/98 all 0.20 VA VA VA1 108/09/10/ 11/12 all 0.24 VA Type Price If) BPX BRIO BR BRC BRY BRY EISS BT BT EIT BU BU BU105/ BU U BU BU BU U BU C106D 0.80 C106F 0.43 C111E 0.46 D4ON E E1222 0,47' E GET ME MF0404/ ME6001 ME6002 MJ2955 MJ3000 MJE340 MJE341 MJE370 MJE371 MJE520 MJE521 MJE2955 MJE3000 MJE3055 MPF102 MPS3702 MPS3705 MPS8521 MPS6523 MPS6566 MPS405 MPS406 MPS455 MPSA56 MPSA93 MPSLO1 MPSUO Type Price ( f) MPSUO MPSU MPSU MPSU MPSU MPU C C C C C C C C OC OC C8ID C C C C C C C C OCP ON236A 0.94 R R R R ST TIC TIC TIC TIP29A 0.47 TIP TIP31A 0.51 TIP31C 0.67 TIP32A 0.56 TIP32C 0.72 TIP33A 0.77 TIP34A 0.84 TIP41A 0.72 TIP42A 0.80 T1P TIP TIS TIS ZTX ZTX Z7X ZTX ZTX For matched pairs add per pair. VALVES Type Price (f) DY86/ DY ECC8I 0.78 ECC ECC83 0.7$ ECH ECL EF EF EF EH EL EY EY86/ PCC PCC PCC PCCI PCF PCF PCF PCF PCF PCF PCF PCL PCL PCL PCL PCL805/ PD PFL PL PL8I 0.94 PL PL PL5I PL PY81/P BRIDGES Rating Price (C) Rating Price (C) V A 100V V V V V V V V V V V A 100V A 100V V V V V V V V V V V A and 25A ranges also stocked. H.V Disc Ceramic () SPECIAL OFFER CAPACITORS I kv 1.5nF 18p 2 pin European battery CONVERGENCE Metallised Paper 3kV 1 5nF eliminators (fits shaver POTENTIOMETERS 2n2F 1500V DC 80p 10n F 500V AC 80p 8kV 10, , socket). 5, 7, , n2F 600V AC 24p 15nF 300V AC 82, 100, 120, 240V: 6V. 200mA p each 3n6F 1700V DC 60p 22nF 300V AC 32p 150, 180, 240V: 6V. 400mA 4n7F 1500V DC 60p 100nF 1000V DC 46p each 240V: 9V. 150MA SPECIAL OFFER 10n F 1000V DC 22p 470nF 1000V DC , 300pF 39p , 120, 270, 470. all at freeeh Quantity prices availabl 209 each VHF to UHF CONVERTER CM6022/RA. Televerta for DX-Ing or unf receiver use on relay systems, Eire etc. I C32.77 Type Price ( 11 ZTX ZTX ZTX N N N N706A N N N N N N N N N N N N N N N N N N N2222A N N N N N N ' N N2906' N2926G N N2928Y N N N N N N Type Price /C) 2N N N N N BIN N N N / N N N P SC458C SC643A SC930D SC SC1172Y SD RESISTORS Mhos eh. minimum el Carbon FOP (MI tool one lopes of any twee. 6. value 5011 WOO. 1W k01E12) 3p P 1 AS 4.W M W W/1E121 3p 24P bp 460 MP W M , 800 MOO 8.40 Wirtzwourid15%) 2IW I8p 4W p 7w p 11W k W p Vertiwi mounting pillars 3p FUSES (all packs of 10) 20mm Time Delay (BEAR) 401n , 63mA mA OrnA , 500, 800mA, 1, 1.25, 1.6.2, 2.5, 3.15, 5A all 3.25 Soldarkig Irons XS -25W 4.09 X25-25W 4.62 CX - 17W 4.62 CS - 17W 4.00 C - 15W MAI Presets Itl 0 1W Normal and Horizontal) 100, , 1.2 2,4 7,10, 22, 47, , 47010, 1.2 5, 5M0 M 14p malt 0 2W (Verticel and Horizontal) ',glossas 1W s8i4sensk ANTE% SPECIAL 20mm quick -Mow (BEAR) 100mA , 315, 500, mA. 1, , 2, 2.5, A all 70p 2A circuit breakers metal 1.62 plastic 1.45 CCN - 15W 4.35 MLXS - 25W 12V 4.75 Ski -Kit 5.09 Replacement Bits 0.60 Stands 1.39 Elements 2.00 ALL THE ABOVE ITEMS NOW IN STOCK - For full information on the Antes range please send S.A.E. MULTIMETER SPECIAL Russian type U4324 -(20,000 0.P.V.) DC Voltage: , 3, 12, , AC Voltage: 3, 6, 15, 60, 150, 300, 600, 900. DC Intensity M/A: 0.06, , , AC Intensity M/A: 0.3, 3, 30, DC Resistance:0.2.5,50.500,5000K. geleveldb: 10 to 12. Price E15 Including pip and VAT. P.S.P.UK: 0300erorder.Chm8.8888:Atcost Please add VAT at 15%. Delivery by return of mail on all stock items. It Is only possible to show part of our range here. Our catalogue ( refundable) shows Service Aids, 7400 series. CMOS. op amps, SCRs etc.. hardware, capacitors. special TV items and many more transistors, diodes, i.c.'s and valves. A/c facilities available EAST CORNWALL COMPONENTS ' 4169VEMEIAir TEL: WEM 10939) UFFICE OPEN: 9.00 AM PM MON-FRI. NEW PROPRIETORS: CAPTIME LTD. 288 TELEVISION APRIL 1983

11 EDITOR John A. Reddihough ASSISTANT EDITOR Luke Theodossiou ART EDITOR Roy Palmer ADVERTISEMENT MANAGER Roy Smith CLASSIFIED ADVERTISEMENTS Barbara Blake HELD OVER The next instalment in our VCR Servicing series has had to be deferred while Mike Phelan took time off to write about conversion of the Philips N1700 series machines for half speed operation. Due to shortage of space we have been unable to include the usual Readers' PCB Service box this month. The service continues in operation and the details given last month (see page 265) still apply. 711IMERN A Touch of the British Disease? Quite recently I was reading an article that commented on a certain country's failure to innovate, lack of investment and excessive reliance on declining industries. The UK? You might well think so - the story has an all too familiar ring about it. But no, it was W. Germany. Not only that, but the main subject of the article was the W. German electronics industry. A day later (really!) I was reading an article on the failure of businessmen in another country to take the initiative in developing and going after new markets: they relied excessively on ageing products in declining markets. Ah now, it must be the UK this time, surely? Not so. The subject was the economic situation in the USA. To cap it all, very shortly after that I was reading about another country where the economy has gone ex -growth, production is stagnating, the government faces budgetary problems and there's concern over increased delinquency amongst school children. The latter subject brought in familiar sounding phrases like latch -key kids. This time it was Japan! Are we to conclude that the whole world is at last succumbing to the dreaded British disease? Perhaps it's more that common weaknesses are being shown up by the present world wide adverse economic conditions. The main underlying causes of the situation appear to be the end, some years ago now, of the post-war boom; a lack of new technical developments to stimulate markets and production; and the consequences of excessive movements one way and another in the prices of commodities, oil in particular. The latter have led to quite irrational moves in exchange rates, further compounding the world's economic difficulties. One could say that it's a case of world mismanagement, though no one's charged with that particular duty of course. Perhaps more to the point one could say that free market mechanisms have failed to work effectively in the economic conditions of the last decade. The problem here is that managed markets don't work any better, as the evidence from E. Europe shows. A return to economic expansion is what's generally hoped for, and the electronics industry, which is by definition innovative, is in a better position than most other industries to provide at least part of the required stimulus. Many things are talked about: the next generation of computers, information technology, ever larger scale integration and so on, with various buzz words like satellites and cable being bandied about to add apparent zest to the prospects. Whether it will all happen is another matter. Large sums are being devoted to computer development - the so-called fifth generation of computers - but will a further massive increase in computer power be necessary, any more than supersonic air travel which seems to have been quietly buried? There is after all a limit to all things: at what point does number crunching become an end in itself? Once you get to this point you leave the world of practical products that can be sold profitably and enter the realm of grandiose schemes - white elephants. The things that have made the biggest everyday impact have been relatively down-market items such as electronic calculators, digital watches and VCRs. VCRs, yes, and this brings us to the curious agreement (see overpage) reached between Japan and the EEC to limit the export of Japanese VCRs to EEC countries over the next three years and to increase the "floor price". The Financial Times didn't like the look of this one bit - a drift towards managed trade it complained. Why should cartels be set up so that the consumer ends up paying more than he need do for what he buys? Quite so. The agreement is a curious affair, the first to be reached between Japan and the EEC (previous "voluntary" trade restriction agreements have been with individual countries). How it's to be put into effect has been left so vague that the whole thing looks like some sort of bluff. The idea is to help correct the present massive trade imbalance and give the European V2000 system a chance to survive. A production rate of 1.2 million units a year is expected to epsure economic manufacture of V2000 machines, and the hope is that sales will reach the same level. But this cannot be guaranteed of course. The V2000 system has the advantage of some further development capability in comparison to the VHS and Betamax systems, but it came along too late, and whether more sophisticated features and capability will mean much to prospective purchasers is open to question. The continentals have always been prone to over design consumer electronics equipment (think of the Philips K70 and K80 chassis, the extraordinary remote control system used in the Saba H chassis, and the more recent Grundig chassis bristling with sealed modules). One can't help but feel that it might have been wiser for Philips to have entered into a manufacturing agreement with a Japanese concern in the way that Thorn did Ṁeanwhile the Japanese electronics industry seems to be set on moving up market, to the evident concern of the US industry. Considerable successes have already been achieved in the semiconductor field, and the world of large computers is clearly the next aim. What then? The fact is that many lines of development in electronics are reaching their natural limits. The microprocessor for example is the culmination of a technology now some twenty years old. Bubble memories have been proposed and worked on but got nowhere, while some of the proposals now being talked about, for example the use of superconductivity to increase computing speed, would be horrendously expensive. It's possible that the electronics world could catch another British disease - the one that produces symptoms like the R101, the Bristol Brabazon and Concorde. TELEVISION APRIL

12 Teletopics JAPANESE -EEC VCR AGREEMENT After four weeks of negotiations in Tokyo an EEC Commission delegation and representatives of the Japanese Ministry of International Trade and Industry (MITI), lead by the minister Sadanori Yamanaka, have reached an agreement to limit the export of Japanese VCRs and nine other categories of "sensitive" goods, including colour tubes, to Europe. The agreement has been endorsed by the EEC trade ministers. Under the terms of the agreement, Japanese VCR exports to Europe are to be restricted to a total of 4.55 million machines this year, including 600,000 kits for assembly in Europe. The agreement is to last for three years, with export ceilings being negotiated yearly. In 1982 Japan exported 4.95 million VCRs to Europe - the figure for 1981 was 2.85 million. Japanese VCR exports world wide rose from 7.35 million in 1981 to million in The agreement between the EEC and Japan will "align" the prices of Japanese VCRs with those of European producers and "guarantee" European manufacturers sales of 1.2 million units this year (sales in 1982 amounted to 800,000). Quite how the alignment is to be carried out, considering the wide variety of different types of VCRs of varying degrees of sophistication, is not clear. Neither is it clear how European manufacturers can be guaranteed sales if the public should decide not to buy their products. It nevertheless seems that Philips and Grundig feel they have been given a breathing space to get production of V2000 type machines established at an economic level, and in consequence they are expected to withdraw the anti -dumping complaint they had lodged with the European Commission. Control of prices and export totals at the Japanese end is to be put into effect by the formation of a MITI controlled cartel. Philips and Grundig have been under great pressure on the VCR front in Europe: both companies have been operating their production lines at well below capacity, and it's said that Grundig have been making a loss of over 50 on every machine sold. SATELLITE TV COLLOQUIUM The IEE is to hold a full day (9.15 a.m p.m.) colloquium on Unisat-1, the UK's first TV broadcasting and business communications satellite, on Tuesday May 17th. Non lee members will be welcome at the meeting, which is being held at the IEE's Savoy Place, London WC2 headquarters. The satellite is to be launched in 1986 and is being privately funded by British Telecom, British Aerospace and GEC. It will provide for domestic DBS TV reception throughout the UK using dish aerials of less than 90 cm diameter, with regional beams covering the USA and Europe suitable for transatlantic business use and TV links. had hoped to sell some 10,000 players in the UK in No official sales figures have been released, but guesses in the trade suggest that the figure was between two and three thousand. The LaserVision system has also now been launched on the W. German market. Things are all of a sudden livening up in the disc field. Following several postponements, JVC have now announced the launch of their VHD system - on the Japanese home market at the end of the month (April). It seems that Matsushita may launch a rival system at around the same time. In the UK, the RCA disc system has again been on show to the trade. An autumn launch is possible, with the players selling at around 200. BIB's RE-RECORD TAB VHS cassettes have a safety tab which can be snapped out to avoid further recordings being made -a useful feature for preventing accidental erasure. The tab is positioned at the rear of the cassette. What happens if you nevertheless want to reuse the tape? To overcome the problem, Bib have introduced a re-record tab which snaps into the position occupied by the original tab. The Bib re-record tab is reusable and can be easily removed using a small screwdriver or similar instrument. The tabs come in packs of twenty, the recommended retail price being 1.47 per pack including VAT. Detailed instructions are given on the attached display card. TRADE SCENE For the first time since the fifties, more TV sets are being sold outright in the UK than rented. Rental accounts for a much higher proportion of the large -screen colour and teletext receiver market however. The peak year for rental was 1972, when 73 per cent of sets made in the UK went out on rental. According to a recent Mintel intelligence report (available from Mintel, 7 Arundel Street, London WC2R at 45), over 95 per cent of monochrome portables and 80 per cent of small screen colour sets are now being bought, which in view of the competitive pricing policies of retail outlets and the greater reliability of the current generation of sets is not surprising. Thorn remain the largest UK setmaker, with production running at some 700,000 sets a year to supply 25 per cent of the colour market and 14 per cent of the monochrome portable market. Philips also have 25 per cent of the colour market, and around 16 per cent of the monochrome portable market (the portables are mainly imported). Sony, Hitachi and Toshiba all have a share of some ten per cent of the colour set market. A joint statement from Thom EMI and JVC reports that negotiations for Thorn to manufacture TV sets for JVC are at an advanced stage. This seems to be a logical development in the growing collaboration between the two companies. The plan is to supply JVC with models in the 20-26in. range from Thorn's Enfield and Gosport plants. JVC at present import only small screen colour sets and observe a voluntary restraint agreement that provides an import allocation of 10,000 sets a year. The output from Thorn's Newhaven joint -venture VCR plant now goes per cent to Ferguson (Model 3V31) and JVC (Model HR7650) respectively. Most of the rest of VIDEO DISC LATEST the Ferguson and JVC VCRs supplied to the European W.H. Smith have started to stock LaserVision software. market now come from the joint -venture plant in W. The news follows a successful test operation at four of the Berlin. group's stores. A wide selection of discs is now being The latest financial report from Tatung reveals that the stocked by 26 of the company's outlets in Scotland and losses made at the Decca Bridgnorth TV plant have been England - the discs retail at It seems that Philips reduced by two thirds, while Decca's share of the UK 290 TELEVISION APRIL 1983

13 colour TV market has doubled to four per cent. Tatung (UK) Ltd. hope for a further doubling of their market share and a return to profitability in the current year. Production of Korting colour TV sets is being transferred to the parent company's (Gorenje) plant in Yugoslavia. Research, development and pilot production will remain in Grassau, Bavaria. VDU FILTER To reduce VDU operator eye strain, The Power Equipment Co. Ltd., Kingsbury Works, Kingsbury Road, London NW9 8UU is marketing a Swedish made antiglare filter. The filters fit over the screen and are priced at 35 each plus VAT. In use the filter largely eliminates reflections and improves the display's contrast ratio. SONY'S "SERVICE MATTERS" Sony is the latest firm to produce a service bulletin, entitled "Service Matters", for the servicing trade. The bulletin will be issued quarterly by Sony (UK), Technical Publications, Ascot Road, Feltham, Middx. Other firms that publish bulletins for the servicing trade include Philips, Thorn and Hitachi. NEW VCRs JVC have now launched their VHS -C format portable VCR, Model HRC3, on the UK market. The HRC3 comes complete with an EC30 cassette which has a playing time of thirty minutes, a remote control unit, a thirty minute rechargeable NiCad battery, battery charger and carrying case. The compact cassette can be played in a standard VHS machine via adaptor type CP2U which is also supplied with the machine. There are various optional extras including tuner connection cables, a heavy duty battery and a mains adaptor. The HRC3 can assemble edit two pieces of recorded material by backspacing approximately thirty frames between camera takes, creating clean edits. Other features include a built-in r.f. converter; record lock switch to save power between camera takes; automatic quick review; automatic rewind; a power save switch; r.f., video, audio and headphone outputs; microphone and camera inputs; and an LCD tape counter with memory function, also doubling as an accurate tape remaining indicator in minutes and seconds. A new lightweight camera, the GX78, has been launched to complement the HRC3. It weighs just 1.38kg, can record well-defined pictures at light levels down to 50 lux (aperture fl 3), and has a two -speed X6 power zoom lens with macro position for close-up shots. The GX78 can also record stereo sound. Panasonic have added the NV200, a portable using the VHS -C compact format, to their range of VCRs. WILLOW VALE TRADE SHOW The next Willow Vale Electronics trade show will be held at the Tay Motel, Perth, from 11 a.m. to 8.30 p.m. on Wednesday, May 4th. Admission is by invitation which is obtainable on request by telephoning RADIO RENTALS' TV MUSEUM Radio Rentals have opened the Baird Museum of Television at their Swindon headquarters. Amongst those present at the opening were John Logie Baird's widow Margaret Baird, who made the trip from her home in S. Africa, and Leslie Mitchell, who announced the start of BBC TV test transmissions from Alexandra Palace in The museum brings the story of TV to life, with working models, pictures and sound recordings from Radio Rentals' archives. Amongst the exhibits are two sets constructed by Baird himself and a Fultograph machine dating from the twenties. The latter was used for sending still pictures by wire. Groups wishing to visit the museum should apply to Christine Reid, Radio Rentals, Relay House, Swindon, Wilts SN2 2BB. SATELLITE TV NEWS The magazine Satellite TV News, which was started as a quarterly publication in August 1981, is now appearing monthly. Though initially aimed at the consumer, the policy has more recently been to provide full coverage of the industry. Details can be obtained from HRC Editorial Services, Derby Road, Heanor, Derbyshire DE7 7 Q H. PRESTEL MAKE OR BREAK The Prestel service has cost some 40 million and still has only 22,400 subscribers, 95 per cent of whom are business users. Recent efforts to increase Prestel use have included Club 403 (see Teletopics last month) and the Micronet system for home computer users (see Teletopics, December) which has now come into operation. There are at least 600,000 home computer users in the UK, so the system could well give Prestel a much needed boost. British Telecom state that they hope Prestel will be in profit by 1984/5 when, incidentally, the computers are due to be replaced (only six are actually in use, the other sixteen being redundant). If Prestel doesn't begin to show a profit by then the whole system could be scrapped. NEW BOOKS "Tomorrow's Television Today" by Michael J. Stone has been published by the author and is available at 9.85 plus 65p post and packing from 47 Filton Avenue, Horfield, Bristol BS7 OAQ. The subtitle is "a handbook on satellite television reception", which is just what it is. There's been a great need for a book such as this, which discusses the technicalities of satellite reception in a practical manner. There's no circuitry, but much information is provided on aerials and receiver systems, with details of the satellites visible from the UK, plus a computer (Commodore PGT) programme and a Cassio programmable calculator programme for satellite location. The latest, sixth edition of "Beginner's Guide to Television" has been revised and brought up to date by Eugene Trundle, who should need no introduction to readers of these pages. An excellent introduction to the subject. The RETRA 1983 "Year Book and Directory", published to coincide with the Association's fortieth anniversary, has been greatly expanded in comparison to previous editions and now runs to 376 pages. Up to date lists of addresses and suppliers are always useful to have, but this directory includes much else besides. Available to nonmembers of the Association at including post and packing from RETRA, Newington Causeway, London SE1 6BE. "Basic Colour Television" Part 1 has been published by Technical Press, Freeland, Oxford OX7 2AP at 4.95 net. Parts 2 and 3 will complete the coverage of the subject and are due for publication this month. The work is described as a "basic training manual" and forms part of the "Common Core" series. It treats the subject in an admirably down to earth manner. TELEVISION APRIL

14 Fault Report Battle with a G8 After a few years of TV servicing I think most of us acquire prejudices against certain models and a respect, even fondness, for others. Which models fit into which category varies as widely as the engineers whose opinions I've sought. My own favourites are probably no better than anyone else's - it's perhaps just that certain designs accord better than others with my jumbled brain pattern. Anyway, a chassis I favour is the Philips G8: a power supply panel that anyone can understand, the chassis at mains neutral, the tube heaters powered from a mains transformer and so on. The trivial needs and common tasks a:e well established - line output transformer and thyristor rectifier/regulator replacement and, as in the set in question, the BU105 line output transistors. The set was an early one and had simply "gone off' after about a quarter of an hour's use. With the back removed we soon established that the power supply was working. Check the 800mA h.t. fuse on the line scan panel: it had blown catastrophically, so I decided to replace it and see what happened. This time it held, but on measuring the h.t. line the voltage was found to have fallen from 205V to around 150V. The line output stage made not the slightest noise whilst in this condition - no sparking or straining noises from the output transformer - and on removing plug PC1 which connects the h.t. to pin 11 of the line output transformer the voltage returned to 205V. So I assumed that the line output transistors were short-circuit, quite rightly as it happened. In went a couple of BU208s, my standard cure-alls, and after disconnecting the tripler I switched on. We now had nothing: fuses intact, 205V line correct. A bit of fruitless stabbing about occurred at this point. I even brought in the scope to check waveforms (since retiring the Cossor scope in favour of a modern transistor job I've had a greater tendency to do this). By now at any rate I'd alighted on the right area: given that virtually no current was being drawn and the 205V supply was present, something in the lower half of the line output stage was clearly amiss. The meter was dabbed across the lower transistor's emitter resistor, which was proved to be intact. More fruitless stabbing and headscratching, then I decided to confirm the resistance reading again - this time from the transistor's emitter pin to deck instead of across the resistor itself. The reading was about loon instead of Well, the wiring on the top line drive board had become extremely scabby, brittle and dry -jointed to the board - in a manner more akin to what you'd expect of a hybrid set. In one of those I'd have suspected something like this to start with, but I find it difficult to credit such frying in a solid-state set and don't go for it quite so readily. Having taken the line drive board out to unsolder the transistors, I'd obviously aggravated the problem. So the most thermally stressed wires were replaced, and after running the iron over all the lands on the board and retinning them I refitted the board. Fire up, and joy at last. There you are then: even in a favoured set you can't always proceed by logic alone, and fundamental suspicions should not be overlooked just because "fried dry -joints Notes on TV faults from Nick Lyons, Richard Roscoe and Mick Dutton are not common" on the particular model. The new transistors should in theory have been balanced, though I must confess that I don't usually bother unless there are obvious problems. This is because: (1) They probably aren't far out anyway. (2) The coil is probably fried and the core jammed, or will jam when you move it, usually at a worse point than initially. And such mucking about with an old coil always ends in tears! (3) BU208s, which are what I always fit, are much more robust than the original BU105s and tend to withstand a bit of disproportionate loading with better grace. N.L. Decca 100 Chassis Why oh why do the triplers fail so often in the Decca 100 chassis? Nearly every one of those in my patch has had a new tripler at some time. In fact whenever I see a blown mains fuse in one of these sets I disconnect the tripler and replace the fuse without making any further checks. On switching the set on everything else returns to normal - well nearly always, anyway. On this particular set the fuse blew persistently, and violently at that. Now if there's one bit of gear worth its weight in gold it's my trusty variac. I find it essential with all these chopper and thyristor power supplies around. Well, on winding the variac up slowly the set worked. Why, knowing my dislike of thyristors and anything to do with them, I had to prove beyond doubt that every other relevant component was o.k. I don't know. What I should have done was to suspect the thyristor of some perverse problem and replace the damn thing. After all, they're not expensive. What I did however was to prove that the thyristor would short again when connected to the mains supply directly. I connected the wretched thing to the AVO, provided a dummy load, forgot to remove the crowbar, switched on and bang, another fuse gone. The crowbar had tripped and the thyristor didn't like having rectified national grid supply fed to it directly at switch on. So I finally replaced the device, as I should have done to start with. I also replace the crowbar thyristor on such occasions in case the heavy current it's passed on tripping, especially after repeated tripping, has damaged it. This done we had another bang at switch on. The poor old bridge, by now sick of all this heavy pulse work, had succumbed. After this was dealt with everything was back to normal, the tripler being innocent all the time. N.L. This Plug Business... So I'm not the only one who's irritated by this plug removing business - LLJ complained about the same thing some time back. I bet over half the sets I get from domestic customers have had the plug removed before the set's brought in. I can't help challenging the odd customer about this. A common excuse is "I didn't know whether you had square pins or round, so I took it off just in case." That's a two-edged snub for a start, implying that I'm so archaic I still have 5A sockets and that I'm incapable of making up an adaptor lead. 292 TELEVISION APRIL 1983

15 L00K1 Phone: L 3UT701 NB BEDS. OPPORTUNITIES TRADE SALES ALL SETS GUARANTEED COMPLETE OVER SIX HUNDRED SETS ALWAYS IN STOCK Pye 20T, Philips G8; Ferguson 3-3k5 Murphy, Bush, Decca, GEC All from Square Screen, Mono's from 5.00 ALL MODELS Sets for spares from 2.00 All include VAT OPPORTUNITIES 9A, Chapel Street, Luton, Beds. LUTON p.m. Weekdays, p.m. Sundays. Switch to the biggest wholesaler of quality late model used TV's Thousands of Quality Sets always in stock Colour/Mono/VCR's and Audios available Murphy/Pye/Philips/Sony/National Panasonic and other big names We are big - we buy in bulk - we offer you the keenest prices Cash and Carry or we will deliver New and used stands always in stock FREE CAREER BOOKLET Train for success in Electronics Engineering, T.V. Servicing, Electrical Engineering-or running your own business! ICS have helped thousands of ambitious people to move up into higher paid, more secure jobs in the fields of electronics, T.V., electrical engineering-now it can be your turn. Whether you are a newcomer to the field or already working in these industries, ICS can provide you with the specialised training so essential to success. Personal Tuition and 80 Years of Success The expert and personal guidance by fully qualified tutors, backed by the long ICS record of success, is the key to our outstanding performance in the technical field. You study at the time and pace that suits you best and in your own home. You study the subjects you enjoy, receive a formal Diploma, and you're ready for that better job, better pay. r-" ELECTRONICS ENGINEERING A Diploma Course, recognised by the Institute of Engineers Et Technicians as meeting all academic standards for application as an Associate. TICK THE FREE BOOKLET YOU WANT AND POST TODAY ELECTRICAL ENGINEERING A further Diploma Course recognised by the Institute of Engineers Er Technicians, also covering business aspects of electrical contracting. =I MI T.V. ft AUDIO SERVICING A Diploma Course, training you in all aspects of installing, maintaining and repairing T.V. and Audio equipment, domestic and industrial. RUNNING YOUR OWN BUSINESS If running your own electronics, T.V. servicing or electrical business appeals, then this Dipldma Course trains you in the vital business knowledge and techniques you'll need. Incorporating MW ELECTRICAL WHOLESALERS Campion House, Franchise Street, Kidderminster, Worcestershire DY11 6RE Name Address ICS ICS Dept F630, 160 Stewarts Road, London SW8 4UJ. (all hours) NM 1=1 IMMILIMI NMI IMM MI= MMMMMMMMMMMMM TELEVISION APRIL

16 SEMICONDUCTORS BC153 BD131 BU p 13C p ME0404 7p p BF131 ME0412 7p BC172 7p BF240 Op ME6002 7p 8C208 7p BF255 NKT241 7p 8C237 BF256c 35p NKT276 BC238 7p BF256LC 35p PN107 7p BC250 7p BF257 R2010B 1.00p BC251 7p BF259 R BF274 R p p 8F337 R BC347 7p 6F391 7p RCA16446 BC394 7p 6F394 Op TIS90 BC455 7p p TIS91 6C546 7p BF596 7p p 6C549 7p BFR BC556 7p BU105 7Sp 2SA473 12p BC559 7p BUM 1.00p 2SC346 7p 8C595 7p p TICI06C BCX p R p MIXED PACKS DIODES 300 mixed resistors mixed valve bases 1.00 AA112 Bp 8ZU15C12R IN2070 Op AA119 Op 14p 1N52540 Op 300 mixed capacitors spark gaps 1.00 AA143 Op BY204 Illp IN4742A Op 150 mixed electrolytics pin awl IC socket 90p BA115 Op BYX71/400 Ilp 1S025 Ilp 6A131 Op BZY79C 20V Op 100 W'W resistors assorted T V knobs 1.00 BA154 Op Op CV9 8AI57 Op DA002 Op Op 20 mixed cony pots pin Quil to Oil IC Op 1M Op 2X150 Op 40 mixed potentiometers 1.50 socket 90p EI p tp SKE1/02 18p BY127 12p Op MR mixed sliders mixed diodes 1.00 BY133 MCR41:43 35p 40 mixed presets 60p 50 mixed mica washers 65p INTEGRATED CIRCUITS 20 mixed VDR & 300 mixed resistors & BAV40 SN74123N TBA thermistors 1.00 capacitors /M/ SN74154N 1.40 TBA1440C C/M/ N TOA mixed ferrite cores pin Dil to Dil IC DM74123N SN6622N TDA2690A SNI5846N TAA TBA540 90p socket 1.00 IeI-10F 0 purpose mums WA I00, them b.sse itt CVC p 4023 red green brae stab 'rules 1, S1 e ire leers! 0W Ito SCOT p rhor MAO r.ml t I,hit1 psi SER 75p Ph,hps se:,y 125 seutt.e,1 tl030h ,11i t.11,p Tor.n1h.t) r1 R posh bum warn rsr /OK ] ii p0,11 bull". at p0., v ' 1 00 Vest,uae, at presets flt-illtb- FlerlzooLe or goo, tturt. ar at.e.rlarrt 10 of any value 1.00 E.H.T. TRAYS Thorn 6000 EHT Thorn doubler 3.12 Pye 18' early type LP PYE Pye 18' late type 4.00 Thorn Thorn 900/ Thorn Thorn E.H.T. STICK FOR THORN 950/1400/1500 triplers E.C.T. type 80/150 5p E.H.T. stick. 83/200 5p FUSES 20mm 50MA 10 for 70, 500MA 10 for 315MA 10 for I Amp 10 for Thorn 3000 metal 2A cut out 1.25 Thorn 8500 plastic 2.5A cut out 1.25 Degauss thermistor PT37P ITT/GEC + fits some Pye/Bush etc. Degause VDR type 82990/H P /8000 TRANSFORM EAS/LOPT Mains TX 3030/ Mains TX 8000/ SO.P.T, 8000/ /3500 Scan TX /3500 EHT TX LOPT LOPT LOPT Mono portable LOPT. Thorn, GEC, etc Mullard diode splitting LOPT. GEC, etc DROPPERS Pye Pye Thorn K Thorn 56+1K Thorn (5+317 Thorn RBM TV R 28W W sop 90p Thorn focus pot Thorn focus pot 1 00 IC inserters 16 pin 50 p Large IC extractor Crystals MHz EHT lead for split diode I OPT 1.00 Litesold 20 watt 240V soldering iron element 65p each or 4 for 2 00 EHT final anode cap 47p 6MHz ceramic filter ITT bridge rec FXS 244 2A Castors. sets of Direct panel mounting 20mm fuse clips pair for WIRE WOUNDS 1.5R 5W Thorn 3K 27005W 159 1R 5W Thorn 3K 30P W 16p 2.2R 4W W 23p 33R 9W R 5W I5p 4R 11W fusible 25P 33097W 16p 79 9W fusible 25P W fusible 8.2 7W 15P Thorn IOR 7W 15P W 23p 12R 9W 20P 82094W 15R 5W fusible 1K2 9W Thorn 3K/4K lip I5R 7W 16P 1K2 11W fusible 2Sp 15R 11W Thorn 3K 301, 2K2 5W fusible 15R 17W 23P 2K2 7W 16p 22R 4W K2 7W fusible R 9W fusible 25P 2K2 9W fusible 2707W 16P 2K3 5W 27R 7W fusible 25P 2K7 9W fusible R 17W 23P 3K9 5W fusible W W 820 9W fusible 25P 4K7 7W fusible W fusible 259 5K1 7W 16p W Kortint, 8K2 7W fusible 8K2 9W 8K Thorn 23p 220R 17W 23p 10K 7W 235R 9W fusible 10K 9W 16p 240R 9W Thorn 4K 39K 4W EX -EQUIPMENT SPARES )..1 1, ' P each. each [Ir 65p r.,real 65p each rte IF decoder panel Es equipment untested 4 75 Mains on off switch rotary Mains on off switch push Al switch Thorn Al switch Thorn 4000 Ids ITT Pye A 1 pot 5M p 100K 40 turn pots for v cap tuners Double fuse holder on small pax board 120mm type) Single fuse holder on small pax board 120mm type) 5p to line fuse holder 11. type) 3.3PF 6 8PF 8.2PF 10PF 12PF 22PF 30PF 47PF 182PF 250PF 330PF 330PF 330PF 470PF 560PF 1000PF 1500PF 1800PF 2700PF CAPACITORS 350V 3000PF 63V 3300PF 350V 4100PF 350V.0047MF 1000V 0075MF 63V 01 MF 63V.01MF 350V.015MF 63V.02MF MF 63V.022MF 160V.047MF 8KV.1MF 250V.1MF 63V.22MF 250V.33MF 250V.39MF 160V.47MF 63V Any 10 g HIGH ROAD, NORTH STIFFORD, GRAYS, ESSEX, RM16 1UF. (Mail Order Address Only) Delivery within 28 days. PLEASE ADD 60p P&P, PRICE INCLUSIVE OF VAT, ADD POSTAGE FOR OVERSEAS ORDERS THOUSANDS OF ADDITIONAL ITEMS AVAILABLE, ENQUIRIES INVITED 2KV 250V 400V 500V 2KV 250V 6COV 400V 200V 25W 250V 400V 250V 2KV 40W 250V 250V 250V Ea equipment untested panels any specified panel 3.75 UHF aerial socket & lead Pye. Thorn UHF aerial socket & 'sad 3EC derod, +or het & long pad GEC 35p UHF aerial0ri4atosoneket & mounting bracket tnr UHF 71/ aerial for portable 625 aer'ats fillings available Price list on request Coax plugs 12p S witched flush filling aerial outlet Iwhotei MF63V 1 5MF 63V 2.2MF 25V 4MF 64V IMF 350V 6 8MF40V 1.3MF 40V 10MF 160V 15MF 16V 15MF 63V 22MF IV nmf4ov 22MF 63V 22MF 160V 32MF 275V 33MF 40V 33MF 50V 33MF 250V 47MF 350V 50MF 25V 68MF 250V 130MF IV ELECTROLYTICS 20/E1 100MF 100V 10/E MF 160V 10/ 1 20/E1 125MF 16V 10/1 20/E1 150MF 25V 20/1 10/E1 160MF 25V 20/E1 20/E1 160MF 40V 10/E1 20/E1 220MF 40V 10/E1 10/E1 250MF 25V 16/E1 20/1 330MF 10V 20f1 20/1 330MF 35V 10/E1 20/1 330MF 63V 10/E1 20/1 470MF 6.3V 20/E1 20/E1 470MF 10V 10/1 10/E1 470MF 25V 10/1 10/E1 470MF 40V 10/E1 20/E1 640MF 10V 20/E1 20/1 680MF 16V 20/E1 10/1 680MF 40V 10/1 10/E1 1000MF 101/ 10/E MF 16V 10/E1 10/E1 2200MF 25V 6/1 10/ 1-10/ MF 25V I wish to pay by Access. Access No. Amount NAME ADDRESS Signature CARBON RESISTORS 120 LW, 22R LW, 27R LW, 390 LW, 56R LW, 56R LW, 620 1W, 680 LW. 680 LW, 690 LW, 750 LW, 820 LW, 100R LW, 1209 LW, 1209 LW, W, 1504W, 180R 1W, W, W, 2409 LW, 240 R1W,27013 LW, 27081W, 3000 LW, 3300 LW, 4700 LW, 5600 }W, 5800 LW, W, 820 RI W, 1K LW, 1K 1W, 11 2W, 11( 54W, 1K 5 1W, 11(134W, 2K 2.1W, 2K 7.IW, 4K 7PW, 11K 12K 4W, 16K 2W, 22K IW, 33144W, 36K LW. 47K LW, 68K 4W, 100K 9W, 110K SW, 270K LW. 330K 4W, 330K I W, 390K iw, 500K LW, IMEG LW. I MEG 2W, 2M 24W, 2M 7LW, 4M 7.1W, 10M LW any 10 for Thorn 9K thick film units FRI or FR Meg thick film focus resistor 65p MULTI SECTION CAPACITORS of h.,r-,.k p 1 ' V 60p rile,1 v r^," 'K'190 )n315 'Nu I dK +i v. '4)1w 70p r l.4/'=v 65p )))) `r ) CAN TYPES 'W. V SOp '''.9," '.v /Op,,,ii 'I` VF 4r 4 Nip `-^2.1. 3' (7./.. t/f- ' VI I' J 4 termi: 41 'e Tr, r 65p MI v /I d14'.v,p,:.:-mf 41.4 '" - 4K 130 4K 'Ml '.,` Mr )).)v 65p dk 90p d "111 41/v 65p Ml 1M1 1,S SOp 80p r'si:_mf /,0 60p 294 TELEVISION APRIL 1983

17 Another popular excuse is "the set's in the hi-fi cabinet and I have to take the plug off to thread the lead through the hole in the back". Well, it's better than the last one, but try following it up with "oh, so you've brought the plug with you then" whilst holding out your hand. A modification to this is the "I've a long extension lead and didn't think you'd want it trailing around" brigade. The reply that really gets me however is simply "well, they're so expensive now, aren't they?" The chap with the ancient G8 runs a removal business and tells me they get similar trouble with castors and the like... N.L. Monitors Monitors, or at least those built as such instead of being adaptions of a standard chassis, are a breed apart. They don't have that mass produced look about them - in fact some have a distinctly cottage industry look, being hand wired on a short production run. This all too frequently means that they seem to have been assembled from the centre outwards, all hand wired of course, the faulty bit inevitably being at the centre. Having suffered two power supply faults in the first year of its life, plus associated potentiometer trouble, the set in question had earnt itself a less than sparkling reputation. After a further six weeks of faultless service yet another problem arose - intermittent smoking with no observable effect on the picture. When we removed it from the case it refused to smoke, so we left it on. No smoke was seen during that or the next couple of days, but we didn't put it back into service since on the strength of its previous efforts, or lack of them, it wouldn't have lasted long. Sure enough it went faulty a few days later, but true to form the symptoms were different. A picture about half the normal size and of exceptional brightness was being displayed: a crackling akin to that of frying bacon accompanied this spectacle. I then did something I'll not forget. I approached the odious object with an e.h.t. meter (30kV full scale), with the aim of checking at the e.h.t. connector. When the probe was brought within about half an inch of the connector's outer cover however a spark of almost unprecedented violence came from beneath. A loud crack accompanied this, the meter shot off the scale, I jumped a mile and dropped the probe. After that I switched the thing off and refused to touch it again. It stood neglected for a month or so, then a colleague decided to have a go. By this time the voltage had started to track from the cavity to the tube 'dag and to the front case member at random. He switched off, did no further tests but rebuilt half the line output stage and most of the power supply. Switching on gave normal service. A costly and time consuming repair. The moral is not to bemoan mass production and look back nostalgically to the days of " hand-crafted" sets: the modern technology does not lend itself to that approach - electronics probably never did. It was just that the basic simplicity of an earlier generation of sets enabled them to work despite cottage construction methods. N.L. Rank T20A Chassis A Co-op 6348 (Rank T20A chassis) came in for service recently. Won't come on the card said, and indeed it wouldn't. The mains fuse was intact however, and the switch -mode power supply was producing a healthy 200V output. Now in normal operation the line oscillator receives its 12V feed from the 36V supply produced in the 4D14 BZY88 8.2V 200V 409 4R ) N400) C1 TBA950 1N V stabilised Fig. 1: Line oscillator start-up circuit used in the Rank T20A chassis. line output stage, via a regulator, so a start-up circuit is required. This consists of 4C19, 4R49, 4D13 and 4D14 (see Fig. 1). Once the line timebase gets going, the oscillator chip is fed via 4R48 and 4D11. So failure of the set to start could be due to a fault anywhere in the line timebase or in the start-up circuit, which is quite a lot of territory to cover. Experience has taught us to check a few likely suspects first however - 4C19 for example, the state of the soldering around the pins of plug 5Z1 on the line output panel, and the line output transistor's base current limiting resistor 5R8 (111). Sure enough, 5R8 was open circuit. Great! Switch off, fit a replacement, then try again. Nothing! We switched off gloomily and decided to make some tea. Then the phone rang, and after various interruptions half an hour had gone before we returned to the Switch on and it burst into life. Good picture and sound, no sign of anything amiss. Tap around the various panels to check for possible dry -joints, but everything seemed solid enough. Maybe the mains plug was not connecting properly? Nothing happened when we jiggled it about, so we pulled it out and then pushed it firmly home. The set went off - but didn't come on again! We decided to connect a 9V battery across 4C17 in place of the start-up arrangement. The set then came on, so the start-up circuit was clearly at fault. But the fault occurred only when the set was switched on shortly after it was switched off. When left for half an hour it had worked perfectly. A glimmering of an idea began to form. We switched off and checked the negative side of 4C19. A negative voltage was present! So 4C19 was not discharging immediately after switching off. As a result 4D13 was reverse biased and the start-up action was blocked until the charge on 4C19 leaked away. The cause of all the trouble was the zener diode 4D14. It's purpose is to limit the start-up pulse to a safe value for the i.c., and to provide a discharge path for 4C19 at switch off. In fact 4D14 could have been faulty for a long time, since a set is not normally switched on and off rapidly in the home. A new 8 2V zener diode restored reliable startup action every time, and the only problem left was how to justify the size of the bill - most of the time had been spent tracing a fault that no one knew was present. R.R. Grundig 1510 The complaint with a Grundig Model 1510 was that it would go dead intermittently. In fact the line timebase was shutting down intermittently due to a crack in the print adjacent to pin 4 of the e.h.t control module. M.D. Decca 80 Chassis The complaint with a Decca set fitted with the 80 series chassis was that it wouldn't change from Channel 4 to TELEVISION APRIL

18 BBC -1 without having to press ITV first. The set is tuned to the Sutton Coldfield transmitter, and would change channels in any combination between BBC -1, BBC -2 and ITV, but when changing from Channel 4 to BBC -1 the a.f.c. would.lock out. The problem was that C3 (0.1µF) which decouples the tuning voltage line had gone open - circuit. M.D. Philips G8 Chassis It's not often that I get an unusual fault on a Philips G8 colour set nowadays, but just recently I've had three in a row. The problem with the first set was that the line hold would shoot off frequency. All likely capacitors and the two zener diodes - one on the timebase panel, the other on the signals panel - were tried, also the line oscillator coil. The problem was eventually tracked down to R521 (1552) going high in value intermittently. This resistor is in the emitter circuit of the reactance transistor. The second problem was an annoying ticking noise on the sound. Removing the plug to the volume control stopped the noise, and when the plug was replaced we discovered that the voltages in the audio output stage jumped in sympathy with the ticking. The fault was traced to the audio coupling electrolytics C2204 and C2201 (both 1.6µF) being leaky when voltages were applied across them. With the third set the problem was an intermittent crackle on the sound - it was a later set (550 series) with the combined i.f./chroma signals panel and rear convergence panel. Tapping the convergence panel would make the crackle come and go, but tapping anywhere else in the set had no effect. The problem was traced to the plug/ socket connecting one of the wires to the blue lateral convergence assembly not making contact - there was no noticeable effect on the screen. M.D. N1700 Speed Conversion Mike Phelan THOUGH they are no longer in production, the Philips N1700 -N1702 series VCRs are well known for their excellent picture quality. Many are now available on the secondhand market for under 100, and represent a good purchase provided you don't need to view prerecorded films. On the debit side, the tapes are expensive and give up to only three hours' playing time. Halving the tape speed will double this with very little sacrifice of picture quality. With the earlier Philips machines (N1500 and N1501) it was necessary to reduce the diameter of the motor pulley to achieve this. The N1700 has d.c. motors however, so we can vary the speed electronically. Doing it this way also has the advantage that the machine can be made to run at the original speed at the flick of a switch. The cost of the components required for the modification is minimal - about D. The N1700's Servos To see how the job can be done, it's useful to consider the operation of the machine's servos. Fig. 1 shows the arrangement in block diagram form. Most of the circuitry is contained in five plug-in modules - to simplify matters the U228 digital lock -in module has been omitted. In the record mode, field sync pulses are fed to the U236 module to provide a reference. They are divided by two and then converted into 25Hz ramps which are fed to sample gates. The pickup heads below the head drum and capstan flywheel provide feedback sample pulses. These are fed to monostable multivibrators which produce trigger pulses to operate the gates. As a result, the gates produce pulses whose amplitudes depend on the sampling time, i.e. the relative timing of the ramps and the feedback pulses. These output pulses are stored in the drum and capstan servo modules U219 and U230, the stores being triggered from the same multivibrators that trigger the gates. In the record mode 25Hz pulses are also passed to the control head via sync module U237 for recording on the tape's control track. The drum servo works in exactly the same manner on playback, except that this time the reference is the 50Hz mains a.c. divided by two. The capstan servo also uses this reference on playback, but the sample pulses are obtained from the tape via the control head. They are routed via transistor TS203 and a monostable multivibrator in module U237, which also includes the playback tracking system. The tape speed depends on the d.c. conditions in the capstan servo loop: i.e. when, on playback, the off -tape control pulses are arriving at exactly 25Hz the servo output voltage is such that the capstan motor is driving the tape at the correct speed. Halving the Tape Speed To see how we can halve the speed, consider what would happen if we already had a tape which had been recorded at half speed. If we play it back at the standard speed, the off -tape control pulses will arrive at too high a frequency. The servo will try to slow the motor down, but even if it managed to slow the motor sufficiently to reduce the pulse rate to say 35Hz the motor voltage would still be too high. So the required correction can't be obtained without altering the d.c. conditions in the U230 capstan servo module. The circuitry involved is shown in Fig. 2. In addition to the sample/store arrangement which sets the correct phase conditions, there's a speed detector which counts the pulses from the capstan flywheel pickup head and in conjunction with a frequency -to -voltage converter establishes an approximately correct speed. The phase control system then takes over. The operation of the speed control circuit is as follows. The incoming pulses are first amplified by transistor TS6, whose output goes to the gate of the f.e.t. TS8 and to the base of TS7. This latter transistor and its associated components form a ramp generator: the slope of the ramp is fixed irrespective of frequency. This ramp is applied to the drain of TS8, which switches on to sample the ramp amplitude whenever a pulse arrives at its gate. The output is stored by the 0.1µF capacitor at TS8's source. We thus have at one of the inputs to the following operational 296 TELEVISION APRIL 1983

19 1 pickup head Sample pulse 7 012V Field sync pulses 7 50Hz mains : 2 Ramp gen NI\ MMV Sample gate Storage U219 Drum servo To drive amp & drum motor Trigger,0047 pulse 56k Storage capacitor Output Capstan pickup head U236 Ramp gen Ramp gen 1\1\ 9 Sample gate MMV )R Storage Speed detector U 230 Capstan servo To drive amp & capstan motor Capstan pulses 10k ' TS6 12k 470k 4k7 4k7 680k R21 620k 022 IOM i Storage Icapacitor 0579] U237 Tape sync MMV MMV Fig. 2: The part of the capstan servo circuit lin module U230) that requires modification for speed conversion. head 7. )R b op TS203 MMV 6 Amp Tracking rum Fig. 1: Simplified block diagram of the N1700's drum and capstan servo system. amplifier a voltage that's proportional to the incoming pulse frequency. We can vary the d.c. conditions by altering the value of R21. Increasing it will lower the speed, so a value of 1.21\41i will halve the speed. The phase control circuit will do the rest. This takes care of playback, but what about record? On record the speed control circuit tries to maintain the reduced speed provided by R21's altered value, but the sample pulses applied to the phase control circuit from the capstan pickup head will be at the "wrong rate, so the servo won't lock. All is not lost however: we don't really need phase control of the capstan on record - Philips do it for convenience, to minimise switching. If we connect pin 17 of the U230 module to about 6V, i.e. the same as the centre of a 12V ramp, the capstan will run evenly at half speed in the record mode, and it's not necessary to switch the circuit back to the original condition for standard speed operation. To sum up the modification then, to get half speed operation we switch the value of R21 in module U230 from 6201M to 1-2MR which we can do by using the spare set of contacts on channel selector no. 8. We also need to break the connection to pin 17 of module U230 on record and connect it to 6V. This can be done with a simple electronic switch (see later). Finally, but only on the N1702, the clock can be made to display five hours maximum of timed recording length - this cannot be done on the N1700 unless an N1702 clock module is fitted, but r L_ r U219 module U230 module U228 U236 U237 module imodule 'module (lock -in circuit) 1 I L J SERVO PCB Print (top) side 0 L 560k _if268 Brown wire,-- R2I a-nsar- / Reconnect here Spare pin Fig. 3: Modifications to the 0230 module. U230 Connector end U230 board (component side) Connect to tuner push button unit Servo PCB (print side) Earth is no great disadvantage because if the switch is not left in the "lock up" position the tape will run to its end. Practical Details To carry out the modification, the first job is to remove the cassette lift by depressing the pin on the left-hand side. Next slacken the two screws that retain the top cover - they are at the back. Then remove the cover - this can be a bit of a struggle. The servo board will be seen on top of the tape deck. Locate module U230 and remove it (see Fig. 3). The module plugs in - don't unsolder it. Find R21 and remove but don't discard it, then unsolder the brown wire and reconnect it as shown - in the hole where the left-hand end of R21 was. This brings the connection for R21 out to an unused pin (9) on the edge connector. Connect a length TELEVISION APRIL

20 Channel selector (print side) Cal 1M2 (original R21) To servo panel r Clock IC (print sidell_ IC ) Connect pin 23 to 12V 2 22 Cut here 12V rail lb) Fig. 4: (a) Speed change connections to the channel selector unit. (b) Clock conversion (N1702 only). of fine twin cable to pin 9 of the edge connector and to chassis as shown, and route it through the wiring so that the servo board can still be hinged up. The cable should emerge near the tuning buttons. The two resistors are fitted on the spare switch on button no. 8 (it's possible to press two buttons in at once when recording). Next, remove the cabinet top half. The four screws in the corners are obvious, but there's a fifth one accessible only when the record key is depressed. The print behind the push buttons will now be visible (see Fig. 4). Fit the new 1.2MC/, inv resistor and the original 620ka one as shown, and connect the twin cable from the servo board. While the cabinet is off you might as well modify the clock (N1702 only) to display five hours instead of three (see Fig. 4). Cut the print with a Stanley knife and connect pin 23 to the line of print that runs between pins 23 and 24. Then reassemble the cabinet half. The final job is to make up the electronic switch, which is easy to do on Veroboard (Fig. 5). In the record mode terminal D provides a 6V output: Trl is saturated by its base bias, shorting the base of Tr2 which is thus switched off. On playback the record 12V supply is inoperative and Tr2 passes the pulse input to terminal D. Solder the board Trl Tr2 --Edge of servo panel. Printed side 0-- C r r A7 134 Cut here" B3 r limmoocp: C Pulse input U230 module 10k 12V A Rec I2V Pulse/ 6V o/p Solder earth edge of Veroboard to link on component side of board A7, B3, 134 connectors o- - Links Fig. 5: Electronic switch to control the input applied to pin 17 of module on and link it up as shown, keeping the leads short. All that now remains is to reassemble and test. With the connections as shown, the machine runs at half speed with button 8 pressed in. It will of course benefit from cleaning and lubrication as per the manual, and if a scope is available setting up the servo adjustments (but don't touch these if you don't have the necessary knowledge and equipment). Letters EARLY TVs WANTED For the purpose of research towards a book on early television I'm eager to obtain any pre-war television receivers, in particular those manufactured by Pye, also brochures and literature. Those who visited the Science Museum history of television exhibition in 1980 may recall that I was involved with this and edited the exhibition supplement. My book "The Story of Pye Wireless" was published by Pye in 1979 and was reviewed in your September issue that year. Gordon Bussey, 64 Pampisford Rd., Purely, Surrey. Telephone (evenings) MAINS FEED PROBLEMS With reference to David Lisle's letter (February page 200) on mains supply problems, particularly in connection with the Philips Gll chassis, I'd like to say that in 90 per cent of cases where I've found mains rectifier, line output transistor or field timebase i.c. faults in this chassis the cause has been a defective adaptor or mains plug. When the Gil first came on the market six years ago I attended a technical seminar on the chassis: even then the Philips technical chaps commented that these sets should not be operated via a mains adaptor, and that only an MK plug should be used. The chassis is very reliable when these points are observed. It should be noted that transients due to faulty plugs/adaptors can reach 1-1.2kV for a few milliseconds. Hence the need for care with the mains supply. Jim Rainey, Bangor, N. Ireland. PHILIPS G11 CHASSIS I fully endorse David Lisle's comments regarding the importance of a sound mains supply in connection with receiver reliability. It's been my experience too that BU208A and/or TDA2600 field timebase i.c. failure in the G11 chassis is sometimes the result of mains supply arcing or interruption. The other common cause of such failures in the G11 chassis is the h.t. reservoir capacitor C4029 going open - circuit intermittently. Monitoring the 153V h.t. rail in a suspect set will reveal the very occasional presence of a positive voltage transition which can result in destructive timebase problems. A defect in C4029 is often visually evident when it's removed from the panel: careful examination of the negative tag may reveal signs of darkening around the rivet head, indicating that it's not to be relied upon. A general rule of thumb is to fit a replacement in all sets employing the red -bodied "Pye" type: the blue type 298 TELEVISION APRIL 1983

21 sometimes fitted seems to be far more reliable. Incidentally the glow switch overvoltage circuit in this chassis is incorporated to provide protection against the effects of long-term excessive h.t. levels (greater than V) and is unresponsive to short-term transients. In difficult cases, intermittent failure of C4029 may be so occasional that a critical combination of voltage surge and temperature conditions is required to being about a timebase fault. Thus timebase failure in the G11 chassis is more likely in a set fitted with a suspect type of h.t. reservoir capacitor and operated from a defective supply. Peter H. Dolman, Dolman Audio Video, Melksham, Wilts. Editor's note: We've received several letters on this subject. Many thanks to all who wrote. C4029 problems have been mentioned before - see S. Simon's article on the G1 1 chassis in the September 1982 issue and Teletopics May Philips recommend the use of a DALY/ITT type (Philips Service code no ). CORRECTION As a recent reader of Television, may I say that I find it most informative? There was an error in the February issue however. The Thorn 1500 chassis is fitted with a PCL82 audio valve (page 191), not a PCL86. B.C. Smith, Weybridge, Surrey. Editor's comment: Yes indeed! Sorry. 12HG7 SUBSTITUTE Some while ago (June 1982) Eugene Trundle wrote on substitutes for the obsolete 12HG7 luminance output valve used in hybrid Bang and Olufsen colour sets. He mentioned that he'd not tried the solid-state PL802 but considered it should work satisfactorily. I've used a PL802T in a 2600 chassis whose 12HG7 had an intermittent short-circuit - a genuine replacement 12HG7 would have been expensive indeed! The procedure is as follows: (1) Remove the 4711 wirewound heater dropper resistor from the PL802T - the 12HG7's heater is fed from a transformer secondary winding instead of being in a series chain. (2) Remove the i.f./tuner/control panel from the set. (3) Remove and isolate the -120V lead from the brightness control. (4) Swap the 561(1/ resistor from one end of the brightness control to the other. (5) Connect a 22ka, iw resistor between the vacant end of the brightness control and the 30V supply. (6) After refitting the panel all should be well! The modified set has been working for many months now and the results have been very good. P.R. Dowding, Dowding and Son, Malmesbury, Wilts. PORTABLE LIGHTING UNIT Lighting problems should be negligible in the workshop. When doing outside work however you never know what lighting conditions you're going to find, so it's desirable to have some sort of portable spotlight to illuminate particular areas. The use of a battery powered torch is not the answer, whilst hooking up a 60W lamp with guard etc. will be rather clumsy. The solution I've devised is a I2V IOW lamp Car reversing light accessory Mild steel bracket Mains supply Aluminium bracket V IA Bell transformer Fig. 1: Victor Rizzo's portable lighting unit. Earth here Flexible piping DM! compact, stable, safe and efficient transformer -powered portable lighting unit which can be easily constructed at moderate cost. The device is shown in Fig. 1, from which it will be seen that the power pack consists of a bell transformer rated at 12V, 1A. The light itself is a car reversing accessory. The one I used is made by Sparto, measures roughly 11 x 5 x 3cm. and weighs a mere 80g. The 12V, low bulb gives a reasonable light output. A 30cm. long, 1 cm. diameter flexible pipe was salvaged from a scrap stand light - if narrower piping can be found so much the better, but the flexible piping used for plumbing is not suitable. One end of the piping is connected to a bracket made from reasonably thick aluminium sheeting. The lighting unit is fixed to this bracket by means of two bolts and nuts. The other end of the tubing is fixed to a fairly thick mild steel plate at least 3cm. wide, bent as shown. Three holes were drilled in this bracket, one to take the piping and the other two for fixing to the transformer. Such transformers normally have only one of the lamination tightening bolts protruding at the top, so the shorter one should be removed and replaced with a longer one. As is common practice with car lighting accessories, one of the lamp terminals is earthed: it's as well to earth the whole thing, the earth connection being taken straight to the flexible piping. Finally four rubber pads were fixed to the bottom of the transformer to stop the unit slipping about. Victor Rizzo, Msida, Malta. BIONIC PYES Some years ago I fitted many solid-state colour -difference amplifier panels to sets fitted with the Pye 697 chassis. These have worked very well, but a fault on the panels can cause concern. This is when the resistor that feeds the luminance output transistor goes faulty. The result can be a severely overrun c.r.t. - in one case the tube was ruined. I therefore replace this resistor with a higher wattage type whenever I get any of these sets in for repair. When this resistor is faulty the beam limiter can become inoperative, with a whole series of misleading symptoms such as smeary pictures, bad focus, the tube neck glowing blue when the brightness is increased etc. On the occasions I've had this trouble the resistor has been virtually open -circuit. P. Smith, Hathersage. TELEVISION APRIL

22 Routine TV Receiver Tests: Thorn 8000 Series Chassis S. Simon LAST month we dealt with the original 8000 chassis. In due course this was superseded by the 8000A, which has a different power supply panel and an extended "mains dropper". These items still occupy the same positions, with the dropper on the left-hand side, mounted vertically, and the power supply panel under the centre section. The important thing to bear in mind is that the power supply panels cannot be interchanged, because the dropper used in the 8000A has two sections which replace two of the wirewound resistors mounted on the original panel, R727 and R729. There are several other component changes, so it's essential to recognise the chassis being dealt with. Apart from the A on top of the steady bracket and on the rear cover, the type of dropper used and its connections will provide immediate identification. The original dropper had only three sections: an 8000 may be fitted with an 8000A type dropper, but in this case the upper sections will not be in use. should be removed in the interests of thyristor reliability - it was deleted in later production. Apart from the trouble spots already mentioned, the main problems concern the line output and e.h.t. sections of the receiver. A faulty e.h.t. unit can kill the line output transistor. Less seriously, it may affect the focusing. Thus a picture that's out of focus may require a new e.h.t. unit to restore normal focus control action although the picture is otherwise unimpaired. This is because the 150MC/ resistor in the e.h.t. unit has deteriorated. Before suspecting the e.h.t. unit however it's wise to check on the presence of a 100kt/ resistor (R609) in series with the focus pin on the c.r.t. base panel. If fitted it could be faulty. In later models it was deleted: so if you find that it's open -circuit, it's quite in order to short it out or replace it with a lower value resistor if this is more convenient. All this is not to say that the focus unit can't be at fault, in fact it often is. In our experience however the e.h.t. unit is more likely to be the culprit. The 8500 Chassis Several major differences were introduced with the 8500 chassis, to enable it to accommodate a larger tube. transformer is of a different type and feeds a different e.h.t. rectifier. This contains a 150MS/ resistor which supplies a different type of focus control unit. The latter supplies some 4.5kV to the c.r.t. base. Another important difference is the line output transistor, which is a BDX32. There are changes in the circuitry around this transistor. The power supply panel is over on the left-hand side, in a more accessible position, while the mains dropper is horizontally mounted just in board of the left -side chassis frame. The la/ surge limiting resistor R721 is replaced with a choke (lower left). The bottom centre section of the chassis has a much less cluttered look. The mains fuse is 3.15AT and is mounted on a panel with other items immediately above the power supply panel. Amongst these items is the 800mA 1.t. fuse and the mains filter capacitor, which may be a single one with a value of 0.22µF or two of 0.1µE each. The mains filter capacitor(s) are suspect if they are rated at 600V d.c. (300v a.c.) - they could well be the cause of a shattered mains fuse, also the mains plug fuse if this is rated at only 5A. Later versions have a thermistor in series with and mounted on the mains input choke. You may well find it with one leg detached (as in the Rank A823 chassis). If the thyristor rectifier is type BT116 or Cl 22N instead of type BRC4443, the series diode may be replaced with a wire link. If the diode is fitted you may well find it decomposed, as mentioned last month: if it's short-circuit, the thyristor should also be viewed with suspicion. The power supply panel is prone to dry -joints, especially around the wirewound resistors, and a general visual check can be rewarding. If capacitor C710 (0.22µF) is fitted as part of the network across the thyristor it The 8800 Chassis When the 8500 chassis was modified to operate a 22in. tube it became known as the 8800 chassis. The main difference this time is a redesigned convergence panel which is fitted in brackets at the top of the cabinet. Pincushion correction is added, and necessitates an extra buffer transistor (an f. e.t.) on the timebase panel to prevent the line pulses interfering with the field oscillator. Other than this it can for most practical purposes be regarded as an 8500 chassis. The first anode presets are still mounted on the c.r.t. base panel, and still give the occasional trouble when one of them goes open -circuit to remove the relevant colour or alternatively result in too much of that colour if the break is at the low -voltage end of the track. Later Signals Arrangements Later models have a varicap tuner. So the front press buttons are voltage selectors. The voltages applied to the tuning line are determined by the setting of the rear vertical strip of controls above the aerial socket. These are part of a panel which is easy to remove and which contains Overwinding:: on n line output P transformer Fig. 1: The c.r.t grid bias/beam limiter arrangement used in the Thorn 8000 series chassis. 300 TELEVISION APRIL 1983

23 the tuner and its supply components - or most of them. The 33V tuning supply is obtained from the h.t. line via a 121(12, resistor (R20) which is behind the mains dropper and a 10ka resistor (R15) which is mounted on the tuner panel. These supply the 33V stabiliser i.c. W2 (TAA550 or equivalent) which is decoupled by C3 ( F). A fault in any of these components can result in complete loss of signals. The drill is to check the voltage at W2 and if this is absent feel resistor R15. If it's hot, W2 or C3 is short-circuit: if it's cold, the resistor is either open -circuit, in which case there will be a high voltage at its h.t. end, or if there's no voltage here R20 is faulty. The panel can also suffer from dry -joints, but by and large if the voltages are right (including the a.g.c. supply at pin 2 of the tuner and the 12V supply at pins 4 and 8), with a variable tuning voltage reaching pin 5, then the tuner itself is suspect (type ELC1043/05). This assumes that there is plenty of noise on the screen to show that the i.f. stages are working, and that the i.f. input plug is properly connected to the lower left of the signals panel. The design of the signals panel changed drastically over the years, the panel used in the 8800 chassis having little resemblance to that used in the original 8000 chassis. Many of the transistors were replaced by i.c.s. Apart from the points mentioned last month, a frequent cause of loss of colour is incorrect voltages at the pins of the i.c.s, particularly at pin 2 of IC5, where the correct 8-8V may not be present due to leakage in the 6.8µF tantalum smoothing capacitor C186. Remember also the likelihood of the crystal being at fault in this range of chassis. The i.c.s themselves are also suspect, but will often respond to warming or cooling in order to identify the faulty one. If the appearance of the colour is delayed after changing channels, a slight adjustment of the lower right oscillator frequency preset R210 may be required - particularly if the associated i.c. (IC5) has been changed. Tube Matters A point we didn't mention last month concerns the bias applied to the tube's grids. The relevant bit of circuitry is shown in Fig. 1. W601 and the zener diode W602 are biased into conduction via R615, so the voltage at the grids should be about 27V. In the event of excessive e.h.t. current, the voltage at the junction of R615/C402 will swing negatively to provide the beam limiting action. The problem that arises is when R615 goes high in value. A negative voltage then appears at the c.r.t. grids and the result is a blacked out tube. A frequent tube fault is a heater -cathode short in one of the guns. This is not necessarily the end of the tube. If the fault shows up as flashing or continuous bright illumination in one colour, the condition remaining when the relevant drive plug has been removed from the top of the signals board, relief can often be obtained by removing the 101(11 resistor R607 from the tube base panel and wiring a resistor of about 47kf/ from one of the heater pins (1 or 14) to the affected cathode, i.e. pin 2 for red, 6 for green or 11 for blue. If the result is smearing of that colour, proving that the short is permanent, this is because of the capacitance of the transformer windings. It's perfectly acceptable to install a c.r.t. heater isolating transformer with low capacitance windings to operate the tube independently of the mains transformer, thus saving the cost of a regunned tube. Such transformers are still available from RS Components - stock no next month in COLOUR SUPPLEMENT! VCR faults provide telltale symptoms on the displayed picture but can be puzzling to those not familiar with VCR servicing. To help newcomers in this field, Mike Phelan has taken a series of off - screen colour photos of common VCR fault conditions. These will serve as a handy reference. With guidance on the course of action to take in each case. EXPERIMENTAL 4GHz CONVERTER Devised by Hugh Cocks as a relatively simple and inexpensive way of converting 4GHz satellite TV signals to an i.f. of 70MHz, this single-step converter features image rejection. Brings those Russian TV signals in clear when used with a suitable dish and low -noise amplifier. SERVICING FEATURES S. Simon's fault-finding guide to the Thorn 9000 chassis, plus VCR Clinic and TV Fault Report. VINTAGE TV This time a look at Baird's ideas for video discs (Phonovision!) and the discs produced by the Major Radiovision Company in the mid -thirties. TEST REPORT The Bi-Pak LOPT tester uses an unusual method of driving the LOPT to test its efficiency. Eugene Trundle has tried it out on a variety of different line output transformers. NEW EHT SYSTEM Telefunken wanted an ultra simple, reliable LOPT for their 415/615 chassis. This led to the adoption of a new EHT rectifier arrangement. Simple and effective, as George Wilding explains. PLUS ALL THE REGULAR FEATURES ORDER YOUR COPY ON THE FORM BELOW: L TO (Name of Newsagent) Please reserve/deliver the May issue of TELEVISION (90p), on sale April 20th, and continue every month until further notice. NAME ADDRESS J TELEVISION APRIL

24 VCR Clinic Reports from Steve Beeching, T.Eng. (C.EI.), Richard Roscoe, Derek Snelling and Mike Phelan JVC HR7700 Several JVC HR7700s (Ferguson 3V23) came into the workshop just before Christmas, all wanted back fast. The problem with the first one was no audio recording via the line input socket - there was also a distinct absence of any audio in the record monitoring mode. This was an easy one, traced to a fault in the 4066 audio input switching i.c. on the junction panel. A 4016 proved to be a suitable replacement. Another HR7700 had a more thought provoking fault. The customer complained that it wouldn't run properly in slow motion, which it didn't. After only a few seconds the speed would accelerate until tape damage occurred. Checking around the capstan servo showed that off -tape control pulses were initially present. They then disappeared as the tape speed increased. The problem was due to misalignment of the pinch roller, as a result of which the tape moved upwards. The control head would then miss the pulses and there would be loss of slowmotion control, the capstan motor running free at a speed close to the forward search speed. I got rather upset with this machine when it severed my MH2 test tape whilst ejecting it. There's no real solution to the problem of tape slack at the end of rewind with the HR7700/3V23 and earlier models, though some measures can be taken to alleviate it. With later microcomputer controlled machines an extra, very short fast -forward pulse occurs after rewind has stopped in order to take up any excess tape. S.B. JVC HR2200 An HR2200 portable machine wouldn't rewind - or for that matter review either. In fact there were no reverse motor functions at all. Checks were made up to and around the microcomputer, and it was found that information was being received but not acted upon. In fact it ignored any attempt at a reverse function, with not even a flicker from a LED. So it seemed that the micro was at fault, and I was cheered by my foresight in having a spare one in stock. This was short lived when I discovered that the type number suffixes differed. A quick call to JVC confirmed that the type had been changed, so I had to send for one. Two weeks later I fitted the replacement. Still no rewind! So I bashed my head against the wall to clear my mind. This must have worked as I had one of my ideas. Perhaps the micro thinks that the tape is at start, as if rewind had just been completed? The answer was yes, due to a short-circuit start sensor phototransistor. S.B. Intermittent Fuse Blowing There have been more than just a few instances of intermittent mains fuse blowing in various machines for no apparent reason. The VCRs concerned are the Sanyo VTC5300 and VTC5000 and the Toshiba V9600, while the fuses are of the 500mA quick -blow type. Fitting anti - surge fuses is not the cure, and I cannot advocate the use of higher fuse ratings, though this will provide an answer. The reason for the fuse blowing is power supply surges, or more to the point transient spikes. These have more effect when the machine is in stand-by, since the extra current drain when the machine is running damps any transients. I have it on good authority from Sanyo that the cure is to replace the 0.1µF mains filter capacitor with one of µF. A 350V a.c. type is required and the RS Components type is suitable. The modification also works with my Toshiba V9600s. S.B. Sanyo VTC9300 Andy usually checks out VCRs before I get my hands on them. Just in case the fault is very simple, like Andy! In this case it was a Sanyo VTC9300, the note with it reading "servo unstable, has tendency to burst into flames." It was the usual story of power supply failure, but this time the 12V regulator transistor had been hot enough to melt its nylon insulating bush. The machine had previously been misrepaired during its guarantee period by a high street chainstore group, and now the customer was going to have to pay for it. Because of insufficient heatsinking, the transistor had overheated and destroyed the driver as well. You may know that the Japanese series regulator transistor can be replaced with a TIP41 - provided it's of the same mounting package and not of the giant sort marketed by RS Components. I recommend smearing RS Components heatsink compound on all the contacting surfaces - transistor, mica insulator and aluminium. After doing all this and setting up the 12V supply playback was fine. But recordings seemed to be in mime and no sound could be monitored in the E -to -E mode. Attention was directed to the sound i.f. panel, where the 12V supply was absent from the detector chip which had a hole in its side. As well as the demise of the AN240 i.c. its power supply filter coil was open -circuit. S.B. Hitachi VT9300 An Hitachi VT9300 had some very peculiar symptoms. In the E -to -E mode the sound was normal but the raster was completely blank. With a prerecorded tape the sound was again normal but instead of a blank raster there were some coloured streaks - as though the chrominance but not the luminance information was present. Scope checks in the E -to -E mode brought us to pin 2 of IC202: the video signal went in but didn't come out at pin 24 as it should. On playback the luminance signal went in at pin 1 but the composite video didn't reappear at pin 24. We decided to replace the chip (voltage checks had been inconclusive), but having ordered, received and fitted it the fault was still present. Since the voltage readings in our manual are clearly incorrect, we spent some time making comparative checks with a known good machine. This left us just as puzzled: the voltages on many pins were quite different and the sync waveform at pin 27 was inverted - negative -going in the faulty machine. We thought the replacement chip might be defective, so we decided to consult Hitachi. A nice man listened to our tale of woe and then said "change CP206, the LC delay module." Apparently components in this can leak and distort the video. This affects the a.g.c. and results in 302 TELEVISION APRIL 1983

25 various problems - anything from excessive gain to no video at all. He also gave us a tip which we happily pass on: if you have problems and suspect CP206 or its associated filter module CP205, remove it and bridge across with wire. If you then get a good picture, the module is at fault. Be careful however - the pins are small and fragile. R.R. Sanyo VTC9300 The problem with a Sanyo Model VTC9300 was a ripple effect on the picture - the verticals were zigzag and wobbly, similar to line tearing and due to timing errors in the rotation of the video head assembly. These timing errors consist of very small drum speed changes as it rotates. The picture was stable initially, but as the machine warmed up the fault became evident. As the servo was found to be stable, the fault had to be due to either the drum assembly or the motor. The symptoms went after changing the motor, but I was not too happy as this could have been a coincidence. Sanyo were consulted and commented that there could still be problems with loose drum bearings - they can be tightened, but not without a torque gauge, as overtightening will result in bearing failure. I've lately been informed by the customer that the machine is fine until it's been running for about five hours. The problem continues... S.B. Toshiba V8600 The problem with a Toshiba V8600 was no colour during cue and review and still frame. In these modes there's a delay line to compensate for colour phase errors. The path to this was obviously open -circuit somewhere, and investigation revealed a capacitor which consisted of two bits of wire sticking up from the print - the body was elsewhere. As the component is mounted beneath a flywheel it seems that the customer didn't sit the machine on its feet and put pressure from beneath, with the result that the main PCB bent and the flywheel beheaded the capacitor. S.B. Sony Rewind Problems Most Sony dealers will know about rewind difficulties with ageing machines - C7s suffer the most, but C5s have their share of problems. A cheap way of curing the problem is to fit a new rewind pulley wheel: a more positive approach is to fit the Retro Rewind kit part no. A A. This consists of a rewind pulley wheel, a metal main drive wheel and a take-up spool turntable. S.B. Mitsubishi HS30313 A Mitsubishi HS303B, brand new and still in the showroom, suddenly refused to respond to the rewind button, while when reverse fast search was selected the machine just switched off. The trouble turned out to be that the tape start sensor phototransistor Q578 (type PN202SR) had become leaky. Fortunately you can check by just unplugging it: if the fault clears, Q578 is the culprit. Incidentally this machine, like many of the newer ones, uses an infra -red emitter for end of tape sensing - so don't be fooled into thinking that the cassette lamp has failed. The machine was put back on display, but two hours later it developed an audio fault. During record the audio through the TV set became low and distorted, and on playback it was clear that the distorted audio had been recorded. The audio in the E -to -E mode and from prerecorded tapes was o.k. however. On checking the symptoms more carefully we noticed that the distortion during record began a few seconds after the tape had started, and didn't occur if pause was selected. From this we deduced that the trouble lay at the point where the system control and the audio signals came together. So we checked around IC3F1, one of the ubiquitous 4066B cmos analogue switch i.c.s. This performs various audio switching functions under the control of the system logic. Sure enough when the delayed record (del. rec.) signal appeared at pin 12 it appeared at pins 10 and 11 as well. In went a new 4066 and back went the machine. Yesterday we sold it. We're keeping our fingers crossed. R.R. Hitachi VT11 An Hitachi VT11 wouldn't record, i.e. when record and play were pressed nothing happened, though all the other functions appeared to be o.k. The first thing to do in a case like this is to check that the safety tab is in the cassette and that the safety tab switch is operating correctly. In this case the latter proved to be at fault. On this machine the switch is operated by a plastic lever which is clipped on to a nylon shaft. It had obviously not been pushed fully home on assembly, as it had risen up the shaft and was no longer making contact with the microswitch. D.S. Hitachi VT9700 A problem we've noticed with some Hitachi VT9700 machines is patterning in the E -to -E mode when record is selected. The patterning takes the form of faint horizontal bars and disappears when pause is pressed. It appeares to be some sort of beat patterning between the i.f. and the audio boards (possibly the bias oscillator, as adjustment of this affects the patterning but doesn't eliminate it). If Hitachi come up with anything I'll let you know. Alternatively if anyone else has noticed the problem I'd be interested to hear from them. D.S. Hitachi VT9500 "Loud noise on sound" was the complaint with an Hitachi VT9500. It worked all right in the E -to -E mode, but as soon as play was selected the sound was replaced with a loud feedback buzz. By tapping the audio board (the long thin one underneath) the fault could be made to come and go. Resoldering the joints in the sensitive area made the fault more intermittent but didn't clear it. Relay RL401 turned out to have intermittent contacts and had to be replaced. D.S. Ferguson 3V01 A tracking problem with a Ferguson portable, Model 3V01, turned out to be due to the tension arm not operating correctly. The spring had come off. D.S. Hitachi VT8500 An Hitachi VT8500 had a severe tracking fault, and as the paint seal on one of the guide poles was broken I thought that the customer had been twiddling and estimated for a complete tape path alignment. This was accepted, but alignment didn't cure the problem. After trying a head, TELEVISION APRIL

26 lower drum assembly (not easy) and a couple of panels to no avail a colleague took a look at it. After a few moments he pointed out that one of the loading arms seemed to be rather close to the head, and sure enough comparison with another machine showed that the guide pole was bent. A replacement pole cured the problem. What the customer had done to bend it I don't know, but luckily the pole was inexpensive and no alteration to the estimate was required. D.S. Ferguson 3V29 A Ferguson 3V29 would occasionally switch off, after which it might or might not start again if the play button was pressed. I decided to connect the scope to monitor the take-up reel and head drum pulses, and sure enough when the fault appeared the drum pulses disappeared. Unfortunately the machine then decided to work correctly for a couple of days. When it eventually failed again I found Miller's Miscellany Chas E. Miller ALL the evidence suggests that if there's to be a bright future for TV dealers, VCRs will play a large part in it. My friends and acquaintances in the trade report excellent business in this respect, and it looks like being another good year. At around 300 the VCR represents astonishing value for money - especially when you make a comparison with the audio recorders of twenty five years ago. The prices of those often reached and exceeded the 100 mark - when a service engineer was lucky indeed to take home 15 a week! Even an old grouch like myself, with a marked distaste for most of today's taped films, is considering acquiring a VCR - now that the classic Ealing comedy films are to be re-released in the new medium. One aspect of the VCR that may match the sound -only era is of owners recording TV programmes off air and never playing them back! (How many reels and cassettes have you got stashed away and never heard?) Another comparable thing is holiday photography, in that the use of a camera or VCR gets to be an end in itself, with the results largely ignored. Which leads me to think about those portable camera/recorder combinations now appearing all over the place. You do realise, don't you, that you could get invited to watch hours upon hours of instant boredom? Maybe it'll lead to a great new sales opportunity for pocket -sized bulk erasers, which could be smuggled in and used to good effect... For this Relief, much Thanks! ' Just about the most rewarding aspect of being a TV engineer for yours truly is that no one can force me to actually watch the programmes. In its earlier days when it was Practical Television, a more gracious age perhaps, the magazine assumed that its readers did a bit of viewing from time to time, between bouts of tinkering. There were comments on programmes and in particular a feature that there were no pulses at the drum pick-up head unless this was unplugged from the board. Obviously something on the board was damping the head. Capacitor C46 on the board is connected across the head, and disconnecting this restored the pulses for a day, after which they disappeared again. The only other likely components were the pulse coupling capacitor C45 (,F, 16V) and the HA11711 servo i.c. Changing these and soak testing the machine for five days cured the problem. Incidentally this type of i.c. is used in several different VCRs, and I've known it to fail on a couple of previous occasions. D.S. Ferguson 3V29 We're getting a lot of Ferguson 3V29s with the complaint that when the machine has been on all day it will go into rewind whichever key is pressed. This is caused by the end sensor phototransistor going leaky. M.P. called "Underneath the Dipole", by a gentleman who used the pen name Iconos. I wonder what he would have made of today's trivia? To be truthful I must admit to watching the occasional programme, though I get the impression that the makers don't really want me to. They delay the start of the proceedings for so long with totally unnecessary title sequences that one gets the urge to switch off in despair. Just how expensive these titles can be was hinted at recently when a forthcoming children's programme had to be scrapped due to the ill health of the principal performer. It was stated that the cost of the abandoned titles had approached 10,000. I'd have knocked up a few of them myself for thirty bob if asked! Public Disillusionment My personal lack of enthusiasm for the programmes seems to be shared by the public. It's been said that disillusionment with TV broadcasting is the main reason for the growth of VCR sales and rentals. At the time of writing this (mid -January) there's much speculation in the press about the slump in TV audiences last Christmas. I had the unprecedented experience of having repaired sets left uncollected in the workshop until well into the new year. In former times their owners would probably have been hammering on the door on Christmas morning! This must be a warning to those smaller dealers and freelance engineers who depend for their incomes largely on TV servicing. I'm sure we'll adapt to the VCR in due course however. Who knows, when the large rental chains start selling off their older machines all sorts of business opportunities may open up. Cable One thing that won't do the smaller man much good is cable. It won't do the big boys much good either unless they can persuade the viewers to cough up the projected 400 connection fee, plus a hefty monthly rental. There was talk of a million customers being expected in eighteen months' time, though things have gone decidedly quiet since the prospective cable operators have had to sit down and contemplate the hard sales task ahead. Having paid out a large sum to get plugged into the cable network, the viewer is going to expect value in terms 304 TELEVISION APRIL 1983

27 of tip-top programmes. There's a limit to what can be done however, as we are already seeing with Channel 4. What programme making talent there is will just get spread around more thinly. I suppose more sport could always be laid on - like our editor, I remain stubbornly unconverted to this aspect of viewing. If this led to the public going over to cable TV in a big way, us independents would suffer a further substantial drop in income. As an ITMA character used to say, it's being so cheerful that keeps me going. The Affluent Society I was depositing some glassware at the local bottle bank last Sunday when I observed a gentleman casting a large colour set (it looked like a Finlux Peacock) into the neighbouring skip. TV sets can certainly depreciate rapidly. Ironically, I've one of these sets awaiting spares at present. The estimate from the suppliers is around 35 and the total cost to the customer will of course be substantially higher. Which is probably why you see so many TVs on rubbish tips. Ike Hodge Get's Caught! Ike Hodge was deep in his copy of Television when I called in to see him the other day. He motioned to me to take a seat, and I perched myself on an old G8 that had definitely seen better days whilst waiting for him to get through what he was reading. He had a look of rapture on his face. "Good stuff this Les Long -Johns" he eventually said. "Does you good a bit of a laugh. That's the trouble with you and me. We're too serious. Dedicated I suppose you could call it." I agreed that he had a valid point, and Ike continued. "Often feel I wasn't cut out for this job. With my sensitive nature I should have been a composer, or a ship's cook. What about you? A successful writer maybe? Well we all have our disappointments. Look at what happened to me the other day, and all because I was too conscientious. It all started with this old bat coming in and asking me to sell her a picture valve. Said this nice young engineer had changed it on a couple of occasions but now he'd left the district. From what she said it was pretty obvious that she wanted a PY500 and I suppose I could have just sold her one and made a quick profit." "Still selling those gash valves you strip out of ex -rental sets?" I asked. "Gash!" he exclaimed. "I'll have you know I do a good trade with my guaranteed used valves." "How long do you guarantee 'em for?" I asked out of curiosity. "Not against going wrong" he said pityingly, "only that they've been used. What do you think my name is? Anyway, my better nature compelled me to offer to fit the valve for her - so that I could make any adjustments that might be needed.did I mention that she lived at a pub?" "You didn't but it figures. You were hoping for a free drink as well as a service charge." He gave me a sorrowful look. "There's something so terribly mercenary about you. Anyway when I got there, and it was a nine mile trip into the country, it turned out to be a real big oldie. A 25in. hybrid. Must have weighed a ton. The PY had gone all right. Soft. But when I put in another it glowed red hot as soon as it warmed up." "Dead short boost capacitor?" I suggested. "Yes, and I didn't have one in the van. I was all for taking the set back and doing it on the bench, but I wasn't going to bust a gut lifting it on my own. And do you know, out of all the customers in that pub there wasn't one who didn't suffer from a bad back or slipped disc or something else that made it impossible for them to give me a hand. In the end I had to come back here and get a capacitor. It was Willy's day off, or I'd have taken him with me the second time. As it was I just had to hope the capacitor would do the trick. So up came the picture, as good as gold, and the tube looked almost as good as new. The old dear was as pleased as Punch and was just about to pay me when there was a right old flash inside the set and a puff of smoke. The rotten tuning capacitor had burnt up and I didn't have one of those either." "You didn't make a second journey, surely?" "I'd no choice, had I? She was already muttering that this sort of thing didn't happen with the other nice man, and I could see there'd be nothing in it if I wasn't careful, so like an idiot I went through the whole procedure again. If I'd known what was going to happen I'd never have gone within miles of the place again. The set worked like a charm for five minutes after fitting the puffer, then pow, the h.t. rectifier, shorted blowing the surge limiter. By now it was near tea time, so I told her the set would have to go back to the workshop come what may. In the absence of any other help I got the old girl to give me a hand. By then it was getting dark and perishing cold. I'd got about half a mile down the road when I realised that the steering was funny. Flat tyre, front near side. Took me ages to fit the spare, only to find that was flat as well. Had to get a tyre bloke out. Took the one wheel for repair and left me waiting there for half an hour. When he came back he wanted ten quid. Right I thought, that's going on your bill madam. Not wishing for a repeat performance, I soak tested the set for a few days. Whilst doing this she phoned to say she was moving and would I return it to the new address? When she told me where it was I knew I was in for more pain. Of all places, she had to go and move to the top floor of a block of flats in one of the worst reception areas in the district. Willy and I najjered ourselves getting the set up four flights of stairs, and when we got it working the signal strength was so awful we had to promise to fit an aerial amplifier. Didn't even get a chance to fit it before the perishing set blew up again. Line output transformer this time, so it was back to the workshop once more with not a penny to show for all the effort so far - and me down the drain for another twenty quid for the amplifier. About three days later madam phones to say she'd prefer a new set and would I supply one? It would have to be a 26in. model because she was used to a big picture." "So that gave you the chance to make up for everything you'd lost so far!" I said brightly. suppose you picked out one of your most expensive clappers?" "I did not" he retorted. "I recommended her to go to Tod Johnson down the road. Said I'd stopped selling sets." "But you're not exactly friends" I gasped. "Why hand him a sale on a plate?" "You figure it out" said Ike with a knowing grin. "Would you honestly want to install one of my quality sets in a top floor flat with aerial problems? As my dad used to say, cut your losses wherever possible - and if you can lumber someone else at the same time so much the better. I've heard that Tod's laid up with a bad back. D'you think I should send him some grapes?" TELEVISION APRIL

28 Digital Counter -Timer Part 1 Tony Jenkins (WKF Electronics) THIS instrument has been designed to provide a convenient and accurate way of measuring, counting and timing events. Applications include checking and setting clock, subcarrier and timebase oscillators, checking frequency divider circuits, measuring time delays, and batch/transient counting. The term digital frequency meter (DFM) is more commonly used, but it's pertinent to point out that a pure DFM will not perform all the functions of which the present design is capable. DFMs do not usually have timing facilities for example, being restricted to frequency measurement. Most of the full -function counter/timers available commercially are extremely expensive. These and DFMs tend to suffer from the limitations of being either mains powered and/or capable of reading only a limited range of frequency, usually to a low resolution. The present design avoids these constraints, offering the constructor the opportunity to build a portable, battery -powered instrument of great versatility. The frequency range is from less than 1 Hz to in excess of 1.5GHz with eight digits resolution. There are full counter/timer functions and a choice of switchable inputs. The basic power consumption is some 10mA (excluding the prescalers), so that well in excess of a hundred hours typical use can be expected from a PP7 battery. In considering the design, attention was paid to cost and ease of construction in addition to the technical specification. The result is a unit which is much less expensive than comparable commercial designs. Interwiring has been kept to the minimum by using the latest display technology. This simplifies construction and makes assembly errors less likely. So we have a convenient to build, cost effective, multifunction instrument that's truly portable. Basic Design The design is based on the Intersil 7226A eight -digit universal counter/timer i.c. This is similar to the well known 7216 but has extra control lines that simplify interfacing with a 7231A triplexed LCD display driver. A block diagram of the complete unit is shown in Fig. 1. From this it will be seen that in addition to the main logic there are two preamplifiers, which are identical, and two prescalers. The power consumption of the prescalers and preamplifiers is considerably more than that of the main logic, so these sections are switched off when not in use, i.e. when the appropriate input switch is not depressed. The main logic is capable of operating up to 10MHz, the prescalers extending the range to some 2GHz. In designing the input selection arrangements the aim has been for maximum versatility in use. Thus input A can be switched to accept TTL level signals (5V) while input B provides input amplification, and input B can be switched to accept TTL inputs while either of the prescalers is in use. The user's "driving experience" will doubtless suggest many useful applications for these facilities. 2 GHz Prescaler 2 100MHz -2Gitz 9V O Main input 10MHz crystal A B C 0 IC6 Decimal point logic 74C164 Multiplexed BCD signal Data inputs P MHz Prescaler 1 10MHz - 200MHz IC4 Timing of IC2 input V ICI 0 Counter 7226A IC5 10mV Annunciate sensitivity Preamplifier logic Input A A 4051 IC2 Display driver 7231A Triplexed LCD display IC3 10mV sensitivity Preamplifier Reference Binary o input eiv encoder Input B B Iry 4532 I - TTL it Address inputs Range switch Function switch Fig. 1: Block diagram of the counter -timer. 306 TELEVISION APRIL 1983

29 Lt R6 0 10n C k2 ITMJ8131 Fig. 2: Preamplifier A circuit. Preamplifier B is identical. Fig. 6 shows the main logic circuitry. The data output from IC1 appears at pins 6, 7, 17, 18 while address outputs appear at pins The latter drive the 4532 binary encoder IC3 which generates a binary coded output corresponding to the selected input. Pins 6, 7 and 9 of IC3 in turn control the address lines (37-39) of the 7231A display driver IC2. These lines tell IC2 how to interpret the incoming data. Each time any of IC1's address output pins (22-30) goes high (logic 1), IC3's enable output pin 15 also goes high. This triggers monostable IC4a, which produces a 50/1 sec delay to allow time for the data and address lines to settle. The second monostable IC4b subsequently provides a trigger pulse which initiates writing of the information into IC2. The circuitry comprising the shift register IC6 and sections of the input selector switch maintains the decimal point in the correct position when the prescalers are in use. Information for the display annunciators in IC2 - these indicate modes, range and measurement in progress - is selected by data selector IC5. This is driven by IC3's address outputs. Fig. 4 shows the connections between IC2 and the LCD display. Note that the display connector has one spare pin at each end - these should be ignored. The Preamplifiers The counter i.c.'s inputs (pins 2 and 40) are designed to be driven by TTL signals, so amplification is required for any other type of signal. There are two identical preamplifiers, for main input A and reference input B. In the design of these consideration was given to input sensitivity and impedance to enable the measurement of low-level signals using standard test leads. The preamplifier circuit is shown in Fig. 2. The initial stage consists of a dual -gate MOSFET to provide a high input impedance. This is employed as a source -follower to drive the common -emitter transistor Tr2 whose output is a.c. coupled to the base of Tr3 by C7. The bias at the base of Tr3 is controlled by VR2A, which with the complementary control VR2B in the other channel are the front panel "offset" controls. The purpose of these controls is to allow the input Main Board and Display Board Components Resistors: 0.25W carbon film, -±5% Capacitors: except where stated C1 1µF 35V tantalum bead C2 1µF 35V tantalum bead R1 10k C3 68p ceramic plate R2 10k C4 68p ceramic plate R3 47k C5 47p polystyrene R4 47k C6 100n 35V tantalum bead R5 10k C7 10n ceramic plate R6 10k C8 2 ceramic plate R7 15M 0.5W (metal glaze) C9 1/.11 35V tantalum bead R8 10k C10 10µF 16V electrolytic R9 100k C11 68p ceramic plate R k C12 10µF 16V tantalum bead SIL1 2k2x8 TC p trimmer SIL2 100kx8 VR1 220k miniature horizontal -mounting skeleton preset Semiconductors: C Miscellaneous: D1 -D4 1N4148 C XL1 10MHz HC18/U crystal Trl BC184L C6 74C164 SW1-10 See text IC1 7226A C SW11 2 -pole, 6 -way p.c.b.-mounting IC2 7231A C8 74HC14 rotary switch IC C9 LM LCD 8 -digit triplexed display TELEVISION APRIL

30 Preamp input IC1 input - - No offset - glitch being counted (Control central) Preamp input IC1 input With +offset True frequency being counted Preamp input ILL 7 With -offset IC1 input Fig. 3: Effect of the offset controls under ideal conditions. ITMJ814] waveform to be sliced at some point other than its average level, so that low-level noise or other unwanted signals are ignored, i.e. not counted into the reading. This desirable facility is often omitted from commercially produced 1C2 7231A +9V I I I C1 C2 C3 C1 o ---I 10n 200MHz input -12-1Y - 1X - 2Z - 2Y -2X - 3Z - 3Y - 3X - 4Z - 4Y - 4X - 5Z - SY - 5X - 6Z - 6Y - 6X - 7Z - 7Y - 7X - 8Z - 8Y -8X XYZXYZXYZXYZXYZXYZXYZXYZ 11 I 1 1 I I. 1_ V V V V V V V V C 1 C C pins n.c. Note: Display connector strips have an extra pin at each end. This is not shown. Fig. 4: Connections to the display. 1N4148 Fig. 5: Circuit of prescaler no VR1 I I 1 I ICCC [TMJ8121 instruments. The action is shown in Fig. 3. The final gain and conversion to TTL level is provided by Tr4. Input capacitor Cl is included to block the d.c. component of signals being measured. Either preamplifier is automatically selected and powered by the input selector switches. The display indicates when the amplifers are off, i.e. the switches are in the TTL position. It's sometimes useful to feed a TTL signal to one input and a low-level signal to the other. By depressing both the TTL and AMP switches the A input will provide amplification while the B input accepts a TTL signal. By releasing both switches, the reverse conditions apply. The B input can also be set for TTL operation while either of the prescalers is in use. To do this, depress the TTL switch and the required prescaler switch. The display indicates whichever combination has been selected, providing a useful check on the input conditions. Prescaler No. 1 Fig. 5 shows the circuit of prescaler 1, which extends the range (set by the 7226A's 10MHz maximum capability) to 200MHz. The input signal is first amplified by Trl and then fed to the 8629 chip which divides the frequency of the input by a factor of 100. As with the preamplifiers, power is applied to the prescaler only when the appropriate input switch is selected. Selection of either prescaler automatically adjusts the position of the decimal point so that the output is read in MHz instad of khz. To Follow Constructional details will start next month. Further component details and the circuit of prescaler no. 2 are also to follow. Printed boards for the project will be available from Readers' PCB Services Ltd. The unit will be available as a full kit of parts or built and tested from WKF Electronics. Further details and prices will be given in a later instalment. TELEVISION APRIL 1983

31 Amp 200 MHz 2GHz Hold Reset 0 10ms Si \ ms S2 lsec S3 losec S4 ANO AN1 VDD TTL 55 C11 T, 0 (!) ANe AN S \ P1r9V P2r9V IC8 I/P 0/P t rrin vss 0 PB3 AN5 AN4 PA3 1 3 \w o Switch pin layout rs, A o o\cr,,0 cr so D pole 4 pole DO R14 >R15 10k 10k 02 o-- D3 PB2 Pl?+5V P2 +5V ado C211 ITMJI A VDD P2, 0/P SK2 B I/P o+ Batt 0 o- DO o D3 o- 04 1B 05 VDD 4 47k X L1 10MHz TC p Released Latched IC8 VDD.pin14 V55 = Pin 7 IC8 74HC14 /7077 PA= preampa PB=preampB P1 = prescalerl P2= prescaler R k C3 68p R2 /7//f7 10k C5 147p R8 S10k 13 C7 12 C p R5 /4/ :1Y-r- C1168p R3 47k R6 10k / M R///TTT IC6 B 74C DO D1 D2 D3 SIL1 D4135 2k2 each VDD ICI 7226A 8 12 Fig. 6: The switching and logic circuitry. 13 D VDD -6- p n IC IC4a 1/ CIO 01 Q2 R10 10k VD 16 VDD 2I22 0p IC4b VR1 220k 1/ I4 Trl R12 10k D3 R9 100k IC R13 d\an 10k 2 1 IC7 3 IC7 0 VDD.pin14 VSS.pin D1 r=1c6 0.1 R11 10k VDD 0101 C9I C121 TO T TO BC VDD T.0 AO Al A2 IC2 7231A ANANANANANAN IC SIL 2,100k each 3 16 VDD j

32 Servicing Skantic Modular CTVs John Brown THE self -oscillating chopper circuit used in the Skantic Models 4751/5151/5661 was dealt with in some detail in the January 1982 issue of Television, along with the 1.t. supply arrangements and the electronic trip circuit. The purpose of the present article is to cover the more common faults encountered in the rest of the chassis. First, customer controls. Selection of channel 8 alters the flywheel line sync time -constant for VCR use. Individual channel tuning controls are situated in the drawer beneath the slider controls - push to open. Each tuning control has its own three -position band switch. Opening the drawer unit disables the a.f.c. Above the channel 1 selector button is the "programmed picture" button. When this is depressed the colour, contrast and brightness assume internally preset levels. The colour and contrast are preset by P006 and P007 respectively: these two controls are on the channel selection module. Brightness is preset by PF01 which is on the decoder panel. Two types of v.h.f./u.h.f. varicap tuners were used. Series 1 sets were fitted with tuner type R632, which fits into a raised black plastic socket with the aerial input being fed to the centre of a screened crossover unit. In some areas of the UK (Southampton and Hatfield for example) sets fitted with this tuner suffered from herring -bone patterning. The problem was overcome by fitting tuner type F6002, as used in Series 2 sets. This is fitted flush to main panel -1 and there is no external crossover. Series 1 sets can be converted to take the later tuner by means of a small, easy to fit conversion panel which is available from Skantic (Luxor UK Ltd., Slough). The i.f. circuitry is contained in the screened can that fits alongside the tuner. Buffer transistor TMO1 (BF199) precedes the usual filter network. The tailored signal enters the MC1349P i.f. amplifier i.c. at pin 4, the amplified output at pin 8 being taken to pin 2 of a TCA270. Pin 5 of the TCA270 supplies a.g.c. to pin 5 of the MC1349P. Transistor TMO2 (BC308B) provides delayed a.g.c. for the tuner, its input coming from pin 4 of the TCA270. PM01 should be adjusted for 8V at the collector of TMO2 whilst receiving a noise -free picture. Snowy pictures can be caused by a number of similar things. Decoupling capacitor CM21 (10µF) goes shortcircuit to remove the 12V supply to the i.f. module. When CM19 (2.2µF) goes short-circuit the 10V supply to pin 2 of the MC1349P is removed. Either CM29 (47/.1,F) or CM30 (22µF) going short-circuit removes the tuner r.f. amplifer's base bias -a fault in the TCA270 can cause TMO2 to turn off with the same results. Buffer transistor TMO1 is prone to going open -circuit base -to -emitter. A second amplified output is taken from pin 1 of the MC1349P. This passes via buffer transistor TMO3 (BF199) and mixer diode DM01 (0A90) to pin 14 of the TBA120U intercarrier sound i.c. The audio output at pin 8 is taken to the audio output module via the volume and tone controls. On Model 5661 a second audio signal from pin 12 is fed directly to the switched headphone and tape sockets at the rear of the set. A word of warning before tackling no sound faults. If the set is a stranger in your workshop, check the small wire link on the power supply module. It should be in the RIS (5W) position. If it's in the 20AX (12W) position the a.f. module will be receiving a 34V supply instead of the required 22V, which results in lots of burnt a.f. chips and still no sound. There are three main causes of loss of sound. The buffer transistor TMO3 can go open -circuit base -to -emitter, while the audio output and TBA120U i.c.s frequently fail. Two types of audio i.c. were used, the TCA940 and SN They are neither physically nor electronically interchangeable. The 100k1/ resistor RLO1 associated with the TCA940 can also go open -circuit to cause loss of sound. The audio output module plugs into the rear of the slider control module. The Decoder The composite video signal enters the decoder module (Skantic call it the colour processing module) at pin XF15. From this point it takes two separate paths (see Fig. 1). One is via CF14, RF27 and the luminance delay line to pin 14 of the TBA396 i.c., which acts as a black -level clamp, beam limiter, luminance amplifer and PAL delay line driver. The brightness, colour and contrast controls are d.c. coupled to pins 9, 12 and 13 respectively. The luminance output at pin 7 is d.c. coupled to pin 3 of the MC1327 colour demodulator/matrixing/pal switch i.c. The second path is via CF15, RF31, CF19, CF23 and spring link XF21 to pin 3 of the TBA395 i.c., which contains the a.c.c., burst detector, 4.43MHz reference oscillator, PAL bistable and colour -killer circuits. The chroma output (less the bursts) emerges from the colourkiller controlled pin 1 and is then fed via CF13 to pin 2 of the TBA396 for application to the PAL delay line driver. After passing through the delay line/matrix circuit the separated U and V signals enter the MC1327 i.c. at pins 8 and 9 respectively. This i.c. also includes the blanking circuits, the RGB outputs appearing at pins 2, 1 and 4 respectively. On monochrome, the voltage at pin 1 of the TBA395 rises from 7.6V to 9V. This turns transistor TF02 (BC238C) on, damping the 4.43MHz trap LF02 to extend the bandwidth. Transistor TFO1 (another BC238C) supplies the pulses for burst gating and black -level clamping. No picture can be caused by CF01 (,F) leaking: this fault can also be caused by the 6.8V zener diode DC07 on the RGB output module going open -circuit. If, when changing channels, the picture goes dark and then slowly recovers its normal brightness, RF18 (1MSZ) has gone high in value. A blank white raster is the result when CF11 (10µF) leaks. Loss of luminance, often intermittent, is usually due to the delay line, especially if it's of the black rod type: it either goes open -circuit or develops a high -resistance leak to chassis. Uncontrollable brilliance will be followed by operation of the electronic trip circuit. Switch off and remove connector XB2 from the RGB output module to disconnect the drives to the c.r.t. cathodes. This enables faultfinding to proceed in a more leisurely manner. The 310 TELEVISION APRIL 1983

33 Brightness ontrast )Colour 011 By 24V PF01 14 CFI4 47 AFOI 9 3 iibv0 V 2 IF02 TBA396 1 LF06 LF07 1,,,U AF02 *ye PF03 IF03 MC1327 Composite video input 24V T LF02 ri TF01 TF02 6 JLine frequency pulses RF21 (4/17) Clamp pulses 08 6V 13 Burst gating PF02 ACC Blanking put es U ref& V ref CFI5 RF31 Bandpass filter LF03/04 etc. 3 IFOI TBA Reference oscillator frequency PF04 7.8kHz PF MHz reference signal _LF Fig. 1: Skeleton circuit of the decoder, showing the signal paths between the three ic.s. 4.43MHz trap LF02 is the prime suspect - it tends to go open -circuit, removing the voltage from pin 8 of the TBA396 i.c. Second suspect is resistor RF21 (100kn) - when it goes open -circuit, there is no line pulse input to the base of transistor TFO1 and as a consequence there will be no black -level clamp pulses to pin 11 of the TBA396 i.c. There are two other possibilities, CF42 (4.7µF) or the 6.8V zener diode DC07 on the RGB output panel going short-circuit. With the colour control at maximum there should be loy at pin 12 of the TBA396 i.c. When the problem is no colour, a useful starting point is transistor TFO2's collector voltage. If this is zero, CF29 (47µF) is probably shortcircuit. If the voltage is 9V, there's no chroma signal at pin 1 of the TBA395 i.c. Remove spring link XF21 and connect a shorting link from the pin next to CF23 to the similar pin adjacent to the preset PF03. If this results in some form of colour information on the screen, check CF20 (22µF), the TBA395 i.c. and associated components. If the result is still no colour, check the video path prior to XF21 and the reference oscillator components. If the voltage at TFO2's collector is 24V, there is a chroma signal at pin 1 of the TBA395 i.c. Check CF28 (10µF), the TBA395 and the TBA396. Unlocked colour can be due to CF32 (0.0047µF). Loss of red information can be due to either coil LF05 or capacitor CF40 (47pF) going open -circuit. Hanover bars are usually due to the PAL delay line going open -circuit - at the LF07 (output) end. The Timebases The sync module contains a TBA950-2 i.c., which functions as the sync separator and flywheel controlled line oscillator, and a discrete component field oscillator. The composite video signal is amplifed and clipped by transistor TX03 (BC237B) on main panel -I, the output from this entering the TBA950 at pin 5 (see Fig. 2). Line drive pulses emerge at pin 2 and are fed to the base of the line driver transistor THO1 (BD232) on main panel -2. To set the line frequency, connect a shorting link between pin 5 of the TBA950 and chassis and then adjust PS03 for an upright, floating picture. Line jitter followed by tearing can be caused by CSI 0 (47µF). Should the TBA950 fail, note that the Plessey type is not a suitable replacement as it requires different values in some of the external component positions. Positive -going field sync pulses emerge at pin 7 of the TBA950. They are amplified and inverted by TSO4 (BC237B) and used to control the field oscillator by turning TS02 on. The field oscillator uses the pnp-npn pair TS02 (BC307A) and TS03 (BC237B) in an astable switch circuit. When TS02 conducts, TS03 will turn hard on. As a result CS02 charges, and when the charge on its lefthand plate approaches the voltage at the emitter of TS02 both transistors switch off. CS02 then discharges via RS12/PS01/RS14, the next cycle starting with the arrival of another negative -going sync pulse at the base of TS02. The output at the collector of TS03 consists of a negative - going squarewave pulse. To set the field frequency, shortcircuit the base of TSO4 to chassis and adjust PSO1 until the picture rolls slowly upwards. Failure of TSO4 causes no field sync. A rolling picture is usually caused by RS12 (130kn, 1%) going open -circuit. RS09 (820n) going open -circuit stops the oscillator and causes field collapse. A field sawtooth is developed across CV01/2 on the field output module. These capacitors charge via RV01/2/4 and are discharged when a negative pulse from TELEVISION APRIL

34 the sync module turns on diode DV02, thus initiating the flyback. This same pulse also turns on diode DV01, in turn switching off transistor TV01 (BC238C). The result of all this is a negative -going sawtooth with a superimposed positive -going squarewave pulse at the collector of TV01. This waveform is amplified and used to drive a class AB field output stage (of the type used in the Decca 100 chassis, Thorn 9000 chassis and Rank Z718/T20 etc. chassis). Height is adjusted by PV01, linearity by PV02, vertical shift by PV03 and EW symmetry by PV04. In the event of field collapse, check that the 40V supply to the field output module is present at pin XV06. The most common cause of field collapse is transistor TV05 (2N3441) in the output stage going short-circuit. In this event the other output transistor TV04 (TIP31A) should continued in next column Simple VCR Servicing Part 3: No Fast Forward or Rewind Derek Snelling No fast forward and/or rewind are probably amongst the easiest of VCR faults to repair, though there are one or two pitfalls for the unwary, particularly with Betamax machines. Let's start with the problem that the fast forward or rewind key won't stay down. Switch off the mains supply and see whether it will then latch. If not, you've a problem with the key latching - probably a worn or sticking latching bar. If the key does latch with the mains off, the problem is that the stop solenoid is tripping the key as soon as it's pressed. If the machine works correctly in the play mode, the stop solenoid and its drive circuit can be eliminated and the problem is probably due to the end sensor circuit operating. In VHS machines this consists of a phototransistor which is usually connected to an i.c. that generates the stop solenoid output - the i.c. deals with a number of functions. Checking is fairly straightforward, and there are no adjustments. In Betamax machines the end sensors consist of inductors whose inductance is varied by the foil at the end of the tape. This in turn varies the output level of an oscillator. The oscillator's output is independently adjustable for fast forward/rewind, and it's not unusual for adjustment to be required - presumably due to component value drift. Adjustment is a matter of setting the oscillator's output level, using a scope in accordance with the instructions in the manual. If you don't have a scope and suspect that a machine might need this adjustment, note the position of the wiper on the potentiometer and then turn it an eighth of an inch anticlockwise. If this doesn't help, try adjusting it an eighth of an inch in the opposite direction. If there's still no improvement it's unlikely that the adjustment is off. If on the other hand this does cure the problem, check Rewind idler Supply spool Belt/r. Play idlerklutch Take-up spool Fast forward idler/clutch (a) Supply spool Fast forward/rewind idler Take-up spool Fast forward/rewind motor shaft with small pulley (14 PS721 Fig. 1: Typical rewind/fast forward arrangements. (al As used in Sanyo mechanically -controlled machines. (b) As used in Hitachi electronically -controlled machines. that the machine will now switch off at the end of the tape, and turn the potentiometer back slightly if necessary. If adjustment doesn't help, the oscillator may be faulty. This is usually in an i.c. and failure is not unusual. If the keys latch down but the machine doesn't rewind or operate in the fast forward mode the problem is probably mechanical. In the mechanically -controlled types of VCRs the power for fast forward and rewind is obtained from the capstan motor via various belts, pulleys and clutches. Problems here can be traced by following the arrangement from the motor to the reels and seeing where the movement stops. Likely faults are stretched belts and worn clutches and pulleys. Pulleys can sometimes be given a new lease of life by lightly roughening the rubber tyre with a needle file and then cleaning with methylated spirit. It the belts etc. are all right, check that the reels are free to rotate in the fast forward and rewind modes and that the brakes are coming off properly. A difference between the VHS and Betamax systems is that in the latter the tape remains laced up during fast forward and rewind. Because of this, several things can happen that increase the tape tension sufficiently to slow or stop rewind or fast forward whilst not affecting play. Possible problems are incorrect setting of the back tension arm, a worn head (check that the appearance is of polished chrome with no dull matt finish anywhere), or a worn upper cylinder (this is on top of the video head and should have a fine, grooved finish - it may need replacing if smooth and polished). The latter two problems are common on the Bush BV6900 and Toshiba V5470 machines. The Sanyo machine's head is constructed slightly differently and as yet I've had no problems with it in this respect. When it comes to electronically -controlled machines, rewind and fast forward are usually provided by means of a separate motor (an exception is the new Hitachi VT11). Because of this the mechanical side is kept to a minimum, consisting of the motor and two pulleys (see Fig. 1). Mechanical problems are therefore rare, cleaning the pulleys and reels being all that's usually necessary. A more likely cause of the problem is that the motor fails to rotate. Things to check in this event are the motor and the drive circuit (a failing with the Ferguson 3V29/30 machines is the circuit protection device in the feed to the motor drive circuit). You may also have to check the logic circuits from the press button through to the drive circuit. Remember that a problem in the end -sensor circuit can prevent the logic circuit going into the required mode. 312 TELEVISION APRIL 1983

35 24 V O 390 Sync module Field output module RVI4 100k DV08 8k2 GOV 560 RVIS 2k7 RS27 1M5 EW symmetry Phase ad 4k7 2k RV02 680k Anti -breathing input 25V 8201 RV12 120k Video input k Flyback pulse 27k VCR switching D502 9k53 Ph, 3k9 14 CSIOL 47 Line freq TBA950/ k TSO4 8C2378 Line drive 22k k RS14 68k RS12 130k PS01 50k 0501 Field hold 8C307A 10k $680 CS r24v R U OV RVO1 560k OVOI 47 DV02 CV CV02 0,47 RVO4 39k 1k5 PV TV01 8C238C Ok, Field 1Mearity Height CV DV03 Feedback 6Bk PV k2 Pre amp TV02 BC k 7\*\, All diodes type Fig. 2: The sync and the line and field generator circuits also be replaced. If TV04 is short-circuit, the driver transistor TV03 (BC327/16) is likely to be faulty. Other causes of field collapse are the coupling capacitor CV03 (47µF), RV16(2.21M) or RV15(2.71M) going open -circuit. In the event of RV15 going open -circuit there will be about 6.5V at the base of the preamplifier transistor TV02 (BC237B) instead of the correct 2.1V. Slight cramping at the top of the picture, usually when the set has warmed up, is caused by the bias diodes DV06/7 (1N4001) in the output stage. Change them both even though they read all right on your meter. Severe top foldover can be caused by a leak in CV03 or a fault developing in TV03. Lack of height, together with fold -up from the bottom, can be caused by RV12 (1201M) going high in value. Slight fold -up on its own can be caused by TV05. The line driver and output stages are fairly straightforward. The driver transistor THO1 (BD232) is transformer coupled to the BU208 line output transistor TH02. Horizontal shift is adjusted by PHO1, linearity by LHO4 and width by PK03 which is mounted on the convergence panel. To gain access to the convergence module, insert a small screwdriver into the slot in the right-hand side of the cabinet: slide downwards to release the spring catch. The convergence module can then be separated from the cabinet flap, revealing a pictorial plan of the dynamic adjustments. If the flyback tuning capacitor CH05 is a gold -coloured µF capacitor, replace it with an µF, 2kV type. It goes open -circuit, resulting in high e.h.t. and severe flashovers. The line driver transistor THO1 can be responsible for intermittent loss of the raster. No raster with RHO8 (6.8n) burnt indicates a faulty tripler. Replace the BU208 at the same time. Lack of width with RHO8 burnt indicates that CH08 (0.015µF) in the diode modulator circuit is faulty. A loud line whistle can be due to either the line output transformer, the line linearity coil LH04, or both. Before ordering replacements it's well worth seeing whether you can effect a cure as some sets suffered from this problem from new. A narrow picture with EW errors can be due to DH03 (SKE4F/2/08), LHO6 or RHO8 being open -circuit. If this is not the case check transistor TKO1 (BC237B) and the associated components in the EW drive generator circuit on the convergence panel. EW errors with full width can be due to DH01/2 (same type as DH03) going open - circuit or DH03, CH13 (0.47µF), LHO4 or LHO5 going short-circuit. If these components prove to be normal, check TK01/2/3 and the associated components. Odd Faults Picture jitter accompanied by a hum bar is caused by the tuning voltage decoupling capacitor CX02 (1µF). Darkened corners of the picture are caused by diodes DX03/4 (1N4148). These three items are on main panel -1. A hum bar which changes its position with changes in the settings of the customer controls is caused by CF01 (10µF) on the decoder panel. RS27 on the sync module was changed from 820k11 to 1.5MQ during production. Related Models Certain models fitted with the 20AX tube instead of the Toshiba RIS tube are fitted with the same basic chassis. These include the 6661 which has touch -button channel selection, the 6662/6663/6665 which have automatic station tuning (AST), and the 5664/5674/6664/6674 which have AST plus infra -red remote control. These models have different field output, audio and convergence modules. There are also additional components on main panel - 2. Models with AST have resistors RM21/22 removed from the i.f. module. TELEVISION APRIL

36 Modern CCTV Camera Tubes Peter Graves THE traditional vidicon camera- tube with its antimony trisulphide photosensitive target has two main disadvantages. First low sensitivity, so that a high lighting level is required. Secondly image bum -in, sometimes permanent, if the camera is left looking at a bright image for any length of time. These problems can be overcome by using doped silicon as the photosensitive target: silicon targets offer good sensitivity and complete freedom from bum -in. This article describes the construction, operation and main characteristics of the silicon diode array (SDA) tube and a variant, the silicon intensifier target (SIT) tube. With the latter an electron image intensifier is added to give a massive increase in the sensitivity. Since both types of tube are based on the use of a silicon diode array, we will consider this first. The Silicon Diode Target A typical SDA tube is shown in cross section in Fig. 1. Electrons from the indirectly heated cathode are focused into a narrow beam by the combined action of the voltages applied to the tube's electrodes and the steady magnetic field produced by the external focus coil. Pairs of scan coils, mounted at right angles to each other, deflect the beam to produce the familiar raster pattern at the rear of the photosensitive target. Pulses are applied to the cathode to suppress the beam during the line and field flyback periods. The target is biased positively with respect to the cathode, typically by 8-12V d.c. The signal current flowing through the external load resistor (see Fig. 3) results in a signal voltage which is coupled to the first stage of the video amplifier. Fig. 2 shows the stages in the manufacture of the target. A silicon dioxide layer (an insulator) is first formed on one side of a slice of n -type silicon. Tiny holes are then etched through the silicon dioxide layer, each hole being some 5ihm in diameter and 12/Lm from its neighbours. A typical camera tube target may have over 600,000 of these holes. Finally a p -type diffusion is applied, with the result that a pn junction is formed behind each hole. A thin sheet of high -resistance conductive material is afterwards laid over the oxide surface to prevent the build up of unwanted charges on the insulator - such charges would interfere with the correct operation of the tube. The completed target is mounted so that the n -type surface is exposed to the optical image that passes through the tube's glass faceplate, the p -type islands being scanned by the electron beam. The electrical connection for the external load is made to the n -type slice as shown in Fig. 3. Operation Each of the pn junctions comprises an individual diode, the diodes having a common cathode and separate anodes. The voltage applied between the tube's cathode and the target reverse biases the diodes, the electron beam acting as the return connection. When the beam touches the anode of each diode, electrons are deposited, charging the very small junction capacitance - the p and n sections form the plates of a capacitor, with the depletion region at the junction of the reverse biased diode forming the capacitor's dielectric. The diode leakage current is very small (a fraction of a nanoampere), and the charge is substantially retained until the beam strikes the diode during the following scan. Nothing much would happen with the target in darkness: the diodes would charge and remain charged. Visible light falling on the n -type surface has enough energy to produce electron -hole pairs in the material however. Under the influence of the standing bias applied to the diodes, the holes move towards the anode of the nearest diode while the electrons move in the opposite direction. As a result, some of the charge produced by the electron beam is neutralised. The greater the amount of light falling on a particular area, the greater the number of electron -hole pairs formed and the greater the neutralisation of the charge at a particular diode. The overall result is that a charge pattern is built up on the target: little charge where the light level is highest, maximum charge where the target remains in darkness. When the beam scans a particular diode, once every 40msec with a 625 -line system, it restores the charge at that diode (until enough electrons have landed to repel further electrons). The effect at the other plate is that a current pulse is produced, these pulses forming the video signal. The target arrangement with individual diodes is necessary because of the low resistance of doped silicon. With a continuous pn sandwich the charge pattern formed by the action of light would leak sideways and be neutralised as soon as it had been formed. Other types of target material have a high enough sideways resistance to maintain the charge pattern between scans. Silicon has advantages however. A silicon diode array tube is almost indestructable from the operational point of view. A camera tube using this type of tube can be pointed at the sun or a welding arc at close quarters without being damaged. This is particularly important for surveillance applications, where accidental exposure to the sun's image, direct or reflected, is a constant hazard. Disadvantages The SDA tube is not without disadvantages. Defective diodes appear in the picture as tiny black or white spots (depending on the defect), and a group can give an unacceptable blemish. The aim in manufacture is to produce targets with a diode defect rate of less than about 1 in 100,000. Another disadvantage is that the tube is more sensitive to red than to blue light (see Fig. 4), the response extending into the infra -red part of the spectrum. In some applications, such as discreet surveillance, this feature can be turned to advantage, but in many cases the infra -red response has to be filtered out to avoid unwanted signals from hot objects. Perhaps the worst drawback is flooding or blooming: if the camera is pointed at a small bright light the image produced on the monitor will appear to be surrounded by an irregular pool of featureless white. The extent of the 314 TELEVISION APRIL 1983

37 Scan coil (part) Glass faceplate Electron beam Cathode [UM Fibre -optic faceplate Lens Scene Electron image focused on target Electron beam Light Photosensitive target Focus coil Mesh Tube electrodes Fig. 1: Cross section through a typical silicon diode array tube. The scanning is orthogonal, i.e. the beam strikes the target at right angles over the entire surface. The mesh electrode behind the target contributes to this effect by reducing the velocity of the beam before it reaches the target. Silicon dioxide layer la) N- t ype silicon slice Holes etched through silicon dioxide layer Fig. 2: Stages in producing the target. Target Load resistor P -type islands Video amplifier lb) Electron beam Target bias V DC Fig. 3: Simplified signal circuit. MO Y. 500, I Blue Green Red Ultra violet' Visible light 900 Infra red Fig. 4: Spectral response of the SDA tube. P -type material diffused through holes to form p -n Junctions FA VA e/i :sr cc) furni. Cathode I Wavelength (nanomet rest pool will depend on the exact arrangement and relative size and brightness of the light and the background - in extreme cases the whole picture can be obscured by flooding. Consider the case of a camera pointed at a small but bright light against a black background. The target diodes under the influence of the light will be almost totally discharged whilst the surrounding diodes will remain almost fully charged. As a result, an electrostatic field will exist between the charged and discharged areas. If this is strong enough, there will be a sideways movement of electrons from the charged to the discharged area. In consequence the area of discharged diodes will expand until equilibrium is reached. The result is a white halo surrounding the light image. A disadvantage compared to the antimony trisulphide IDS77 I Intensifier Photocathode Focusing Target electrode section Scanning section Fig. 5: Simplified cross section of a silicon intensifier target tube. vidicon is that the bias voltage cannot be adjusted to control the tube's sensitivity. The target bias is fixed and depends on the basic physics of semiconductor diode operation: such tubes should not be operated outside the recommended range. To keep the tube operating at its optimum level as the brightness of the external scene changes, some method must be used to keep the amount of light falling on the target constant. The obvious way to do this is to adjust the lens iris, and in many cameras the level of the video output signal is constantly monitored to produce a signal which, via a motorised servo system, automatically controls the lens iris position. Much work is being done to improve the characteristics of the SDA tube. Its sensitivity, about ten times greater than that of the antimony trisulphide vidicon, coupled with its ruggedness and freedom from burn -in, nevertheless makes it a good all round choice for many applications. The SIT Tube In addition to its ability to withstand very bright optical images without damage, the silicon diode array target is tough enough to withstand bombardment by high energy electrons. This characteristic is exploited in the silicon intensifier target tube, in which an SDA target is mounted in the same tube as an electron image intensifier (see Fig. 5). This type of tube can give usable pictures at illumination levels as low as 10-5 lux - say the light from a quarter moon or a dimly lit street at night. The basic arrangement of the electron gun, target, scan and focus coils remains as described above. The image intensifier section is placed in front of the target: it consists of a photocathode with fibre -optic faceplate and an internal focusing electrode. The light input from the lens system is focused on to the flat outer surface of the fibre - optic faceplate, which also acts as the vacuum seal. The curved inner surface is coated with a thin photocathode layer (a complex mixture of sodium, potassium, caesium and antimony). Light photons knock electrons out of the photocathode to form an electron image on the vacuum side - many electrons are emitted where the image is brightest, few electrons in dark areas. A high voltage (kilovolts) is applied between the photocathode and the target, negative with respect to the target. Thus the whole electron image is accelerated down the tube and is focused on to the target by the combined effect of the curved photocathode and the voltage applied to the focusing electrode. Note that the electrons forming the image are not focused into a beam: the image stays intact (in the two-dimensional sense) at the target. The high photocathode -target bias accelerates the image electrons, and when they strike the target they give TELEVISION APRIL

38 up their energy to form electron -hole pairs as before. There's an important difference between the SDA tube and the SIT however: in the basic SDA tube one light photon falling on the target creates one electron -hole pair, whilst in the SIT one light photon falling on the photocathode liberates one electron which after acceleration has enough energy to generate up to 2,000 electronhole pairs at the target. Hence the enormous increase in sensitivity. Gain of the SIT Tube Since the energy given to the image electrons is determined by the accelerating voltage, the intensifier's gain can be altered by varying this voltage. A typical range is 4-9kV, the upper limit being determined by the risk of electrostatic breakdown around the faceplate and the lower limit by the amount of energy needed to overcome the inevitable energy loss at the target. Although the voltage required is high, the current requirement is very low and the photocathode voltage is normally generated by a flyback system driven from the camera's line timebase. This synchronises the power supply with the scanning, so that any interference arising from the supply will appear stationary on the picture. The smoothing of an asynchronous supply has to be much better as intererence from it will drift through the picture, which is a much more objectionable condition. The low voltage supply used to power the e.h.t. generator can be varied to control the output voltage. This is easy to do electronically, and by combining the gain control electronics with the iris position servo circuit the tube's sensitivity can be adjusted to cater automatically for a wide range of illumination levels. A double servo loop is used, set up so that the photocathode voltage is kept constant at about 6.5kV while the lens iris is away from either of its end stops. This keeps the tube's signal-to-noise ratio at its optimum condition. Once the lens iris looses control (i.e. fully open or closed) the intensifier voltage is varied to increase the range over which the tube can be used. With a suitable lens, the tube can be used from midday to deep dusk without attention. To anyone used to more conventional CCTV cameras, the sensitivity of the SIT camera comes as a surprise. Setting up the camera at the extreme end of its sensitivity range must be done in a darkened room, and sometimes the light from the monitor screen can overload it. Perhaps unexpectedly, the sharpness of the picture improves (within limits of course) as the light level drops. The reason for this is that at high light levels the e.h.t. is at minimum with the result that there is slight defocusing. Because of their high sensitivity, SIT tubes are often used for surveillance applications. Another important application is for use in underwater cameras. Intensified Intensifier Tube A further version of the SIT tube, the intensified intensifier target tube or ISIT, uses a two -stage intensifier to increase the sensitivity down to almost the ultimate limits determined by photon noise. The increased sensitivity is obtained at the cost of increased noise on the picture and increased camera complexity - two high voltage supplies and their control circuits are required instead of one. Needless to say the tubes are much more expensive. Alternatives Despite its drawbacks the basic vidicon is still widely used since it's cheap. The CCD semiconductor type of image sensing device has been under development for many years now but remains expensive and has low sensitivity. An intensified version using an image intensifier of the type descibed above is also under development - the whole thing would be only a few inches in length. It will be interesting to see how long it takes for solid-state imaging devices to reach the performance standards attained by thermionic camera tubes. Now and Then I WAS sitting at the typewriter wondering what I could say about that letter of mine in the February issue when this chap walked in. What about the letter? Well it was supposed to be a gentle leg pull of sorts. H.B. had had a brief chat with E.T. - the earthly one from the south coast who writes regularly in these pages. Advice had been obtained and in view of the E.T. mania recently - I'm talking about the other E.T. this time - we thought we'd sort of dress it up. It seems that some readers took it all seriously however, so apologies to anyone who may have been offended. The Chap Now what about the chap who walked in? Well he apparently wanted a used stereo record player complete with speakers - and they had to be good speakers at that. I just happened to have exactly what he wanted, and as it had been around for quite a while I offered it to him for twenty pounds. He though that was rather too much. Les Lawry -Johns "Take it off your hands for ten" said he. I don't bargain with anyone, so I showed him the door and off he went. After he'd gone I got to thinking about it. We really are on the losing end in this trade. Twenty years ago that type of unit would have fetched twenty pounds or more, second hand, with no bother at all. Since then wages have multiplied by ten times or so, but you can still buy a new stereo record player for something like fifty pounds, which makes a used unit seem (to some) dear at twenty. Economics It's the same with repairs. Would the average person be prepared to pay ten times more than they did twenty years ago? Look at it another way. Thirty years ago if we fitted a new 12in. tube in a TV set it would cost the owner roughly twenty pounds. What was his weekly wage then? About ten pounds per week? Now we fit a 24in. monochrome tube in a set for roughly thirty pounds, and what is his weekly wage now? The reason of course is that new 316 TELEVISION APRIL 1983

39 electrical goods are so cheap that to repair them is just not economic, though we still do it. Thus we are poor compared to what we were twenty years ago, and we are likely to remain so. End of moan. The Rank T20 Mr. Grumpy's T20 was a nightmare. We'd fitted a new BU208A line output transistor, and as nothing else had showed up during checks and a soak test Mr. Grumpy had taken it home. We saw his car pull up outside and had an attack of the heart sinks. "It lasted only four hours" said Mr. Grumpy. So we attacked it again. As the BU208A was once more short-circuit we again checked everything but could find no cause. Sure enough everything worked fine when another BU208A was fitted. We kept it on soak test for eight hours this time and it worked faultlessly. So Mr. Grumpy took if off again. And brought it back again. This time we changed both EW modulator diodes, also the 0.91µF scan coil coupling capacitor, and fitted a new line output transformer. Another BU208A was installed and the set given a two-day soak test. Mr. Grumpy complained about the cost of the transformer and asked whether it was really necessary? So we suggested that he try it Tor a few days and if it went again we'd refit the old one. It did, and we did. There was no difference though, and this time the BU208A wasn't short-circuit. The timebase wouldn't start until we shunted the line oscillator's start-up capacitor 4C19 with a 51d/ resistor. Then it started working, and continued when the 5k1/ resistor was removed. The set was left looking into a mirror so that we could keep an eye on it. After an hour or so we noticed that it was loosing width, and before we could do anything it had gone off - leaving some 200V on the BU208A's collector to show that it wasn't short-circuit. We had to start it up again with the 5k11 resistor, so as the 9108 resistor 4R16 in the 12V regulator circuit is notorious for messing about we changed it. The one taken out read perfectly all right, and we still had to start the set by hand as it were. This time it lost width and line hold after a couple of hours, so we changed the TBA950 line oscillator chip. It then worked fine for a long time before line hold was again lost and the set cut out.. I cried but Honey Bunch summed it up in flash. The Dry -joint "Dry -joint" said she. "All right, but where?" "How should I know? I didn't ask you to sort out the knitting pattern last night, did I?" So I stared at the right side line output panel, having stared at the timebase panel for some time. And suddenly I saw it. On the line driver transformer. It was just a thin line rdund one the base leadouts. Like a flash it was resoldered, together with every other connection in sight. The set came on straight away, and has remained all right since. I still have bad drams about Mr. Grumpy coming back, but he hasn't. The Music Centre Mrs. Earlybird brought in her music centre complete with one loudspeaker. It was a Ferguson Studio 20. Apparently her husband had repaired (?) the loudspeaker, TELEVISION APRIL 1983 and after trying it in both output sockets both amplifiers had packed up. I opened up the speaker and found that both leads were plugged on to the same speaker tag. It was thus a complete short-circuit, and after he'd plugged it into one output and killed that amplifier he'd done the same with the other one. We removed the bottom screws and lifted the top off (record deck and cassette). All four if resistors in the ouput stages looked distressed. So we changed them and the four transistors for good measure and tested the unit before putting the top back on. It worked perfectly on both channels. So we put the carboard cover back on top of the ouput transistors and refitted the top unit. It still worked so we put the bottom screws back in and made a final check. One side worked, one side didn't. Smoke came out. Out came the bottom screws and off came the top cover. The two lfi resistors on one side had burnt out. No, only one of them. Funny. I checked the current drawn and it was normal. Fitted another resistor and it kept its cool. Refit the carboard card and replace the top - after a tussle with the radio panel. Everything was o.k. so I refitted the bottom screws and tried again. One side o.k., smoke. By this time it was getting late and I called it a day. The Dream During the night I dreamt that I was a brave knight and fought everybody in a place called Camelot. I was called to the King's chambers and he was fixing a music centre. He unscrewed the transit screws to bed the deck down. Then he looked at me and bowed. "Look you" he said, "when you do this you bed down the record deck and the metal speed selector touches the top of the output transistor heatsinks or one of them and shorts it to earth, doesn't it?" "Yes sire. It does to be sure, but there's a cardboard cover to stop it touching and I keep putting the cover back. I do really." "Listen. Listen while I talk to you. There's a right way and a wrong way of doing everything. Now go." So I went, and woke up. I stirred restlessly until I woke H.B. "There's a right way and a wrong way of doing everything" I told her. "Have you just found that out?" she growled sleepily. "The King just told me, look you." "Look you moron, there may be two ways but as sure as fate you'll always choose the wrong way first. Now go to sleep." In the Morning And so it was that the first job in the morning was to reverse the cardboard cover to prevent the speed selector touching the heatsink when the screws were tightened - after replacing the lfl resistor again of course. If the transit screws had been left to let the deck float it wouldn't have happened. I then took Ben for his morning walk. The Hillman Hunter still has a list to starboard, but now there's a bloody great CB aerial stuck in the centre of the boot. Not looking where I was going I felt unfamiliar ground under my feet. The council have filled in the pot -hole and tarmacked it over. Thank you council. And thank you readers for hoping I wasn't going to get my feet wet yet again. 317

40 Long-distance Television Roger Bunney JANUARY was remarkably active for DX -TV signals. The Quadrantids meteor shower produced high-level "pings and bursts" of signals during the 3rd/4th, with at times evidence of signals in Band III (channels E5/R6/E6), mostly unidentified. There were several minor Sporadic E openings (see later) to provide relief from the bleak weather, and an excellent tropospheric opening over the 19th -23rd produced signals in Bands I and III and at u.h.f. from central Europe. W. German u.h.f. signals were logged as far west as Holyhead, Anglesey. An Excellent Tropospheric Opening The build up to the tropospheric opening started with a slow -moving high-pressure system, and from about the 19th there were French u.h.f. signals at good levels here at Romsey. By the 21st, signals from W. and E. Germany and Switzerland were being received in the south and eastern UK in Band III and at u.h.f. There was a considerable improvement on Saturday the 22nd, when W. and E. German signals at good levels were received in Band III and at u.h.f. well into the midlands and the northern UK. At Romsey I found that Band III was generally more rewarding, with all the channels occupied by W. German signals! Garry Smith (Derby) logged CST (Czechoslovakia) chs. R10 and R11 at closedown on Saturday night, along with DFF (E. Germany) ch. E12. The 23rd was the peak day however. During the early hours DFF was present here at Romsey on ch. E5 with absolutely noiseless pictures, also on chs. E6 and E34. From the logs received it seems that more intense signals were received in E. Anglia and the midlands than farther south. Reception was prolonged through the morning and into the afternoon in the midlands, whereas the signals tended to die away during the mid -morning in the south. Mel Wilson (Anglesey) logged Dortmund ch. E35 during the morning - over a difficult and shielded path. At Cambridge Cyril Willis noted "loads of W. German signals," several UK signals, a French ATV signal (F1EOM) and, unusually, the London free station Radio Horizon on 94.4MHz. During the evening we had the bonus of DR (Denmark) chs. E7/10 in S. Hampshire, with the PM5544 test pattern, but the W. German station count was declining sharply. By the morning of the 24th the rain had killed off everything here apart from NOS (Holland), though reception along the east coast continued during the morning, with intense Band III/u.h.f. signals from W. Germany/Denmark. In general terms then an excellent tropospheric opening for most of the UK, with even Aberdeen enjoying signals from central W. Germany. A rapidly moving cold front on the 30th produced a short period of W./E. German u.h.f. signals along the south coast, while earlier, on the 9-11th, French/W. German signals had been received in the south/south east. Auroras were logged in the northern parts of Scotland on the 2nd, 7th, 15th, 19th (very intense) and 21st. The SpE log is as follows: 6/1/83 TSS (USSR) chs. R1, 2. 7/1/83 TSS R1, 2; MTV (Hungary) Rl. 11/1/83 RAI (Italy) IA; TSS Rl. 14/1/83 RTVE (Spain) E2, 3, 4. 15/1/83 Unidentified film on ch. E3 (1500). 17/1/83 MTV Rl. 18/1/83 RTVE E2, 3, 4; JRT (Yugoslavia) E3; RAI IA; ORF (Austria) E2a. 21/1/83 TSS R1, 2; RAI IA. The random and common daily MS signal pings have as usual been omitted -they are widespread and of short duration (under ten seconds). All in all then an interesting month, and my thanks to the following who sent in reception reports: Mel Wilson (Holyhead), Cyril Willis (Ely), Hugh Cocks (E. Sussex), Simon Harmer (Presteigne), lain Menzies (Aberdeen), Garry Smith (Derby), John Tellick (Surbiton), David Moller (Eastbourne), Brian Renforth (Torquay) and Ian Johnson (Bromsgrove). Ryn Muntjewerff (Holland) comments that during the excellent tropospheric opening noted above a DXer at Horm, Holland, logged RAI-2 ch. E30 from Turin. John Tellick took a portable TV atop the South Downs on the The photo on the left shows s.h.f aerials at the USSR satellite station at Frunze - the main dish and outgoing microwave link dishes. The photo on the right shows the Yagi aerial system for receiving the Ekran 714MHz signals. Photos courtesy A. Wiese. 318 TELEVISION APRIL 1983

41 22nd and found Bands I/III and the u.h.f. spectrum jammed with French signals, including a 625 -line Band III test card transmission from Paris ch. 5 (i.e. the new system). Incidentally it seems that the French fourth channel may not come into operation until March next year. Light on SEBC In the January column we mentioned a signal "SEBC" being heard on 106 MHz during an SpE Band II opening last summer. Ian Carnegie (Glasgow) reports that SEBC stands for Southern European Broadcasting Corporation, whose transmissions come from the pirate station Radio Bavaria Int. The station is in the German-speaking area around Bolzano, the output being beamed towards Munich. The mystery of an AFRTS signal on ch. A2, received via SpE from the same direction at much the same time, remains. The USSR Satellite Service Reference has been made on several occasions to the 714MHz satellite TV transmissions from the Ekran craft at 99 E - the output is high enough for reception throughout the northern/eastern areas of Russia using inexpensive installations. The Orbita series of satellites, operating at 4GHz, also carry downlink material intended for local reception and retransmission. Alexander Wiese has sent us some photographs showing equipment at an Ekran/Orbita ground station at Frunze, south of Kazakh Oblast. For 714MHz reception 32 stacked Yagis are used, each with some 40 directors! A large dish is used for 4GHz reception, with two further dishes to provide terrestrial microwave links. The Eurikon Experiment During the past year most W. European broadcasting organisations have been participating in a common programme that's been broadcast via the OTS satellite, the beam covering the European/Mediterranean area from Finland to Tunisia. Most of the transmissions have been scrambled, though the occasional programme has gone out unscrambled. Six digitally coded audio channels have been used. See photos on following page. News Items Macao: A TV service is shortly to be established in this small Portuguese colony. At present the nearest TV transmissions come from Hong Kong some sixty miles away. Luxembourg: RTL has now started its multilingual "international" TV service, in German from and English , followed by a thirty minute Dutch news programme and a feature film with Dutch/German subtitling, then French news. The service extends into Belgium, South Holland and the Mosel valley in W. Germany. The whole thing is by way of an experiment as a prelude to DBS transmissions, in order to gauge the reaction of the German/Flemish audience. UK: The stereo TV sound tests from the BBC's Crystal Palace transmitter on ch. 33 (see Teletopics, December 1982) have been noted after normal transmission hours, accompanied by a variety of test slides including the rare SMPTE test card. Announcements made on the sound SOUTH WEST AERIAL SYSTEMS 10 Old Boundary Road, Shaftesbury, Dorset. SP7 8ND tel tr )li SI-GAZtdtts391-kitis,,, 410,z 41,4r -Qvc207, -404 SAg'SZ:Elypi. *Pita, *18,944:v 4,0Z44QU'2, 42)s,L1. 7Z0.11r,,, ijzyr ihrb 4' /444 SOUTH WEST AERIAL SYSTEMS - TODAYS AERIAL TECHNOLOGY AT ITS BEST - AND WITH TOMORROW IN MIND. We provide the consultancy and supply the equipment for ALL receiving installations in the VHF/UHF broadcasting spectra. Our EXTENSIVE RANGES of aerials, amplifiers, filters and allied components cover Western Europe's most respected companies including Antiference, Jaybeam, Pye/ Labgear, RS (Components), Wolsey, Fuba, Triax, Polytron, Teldis, Vorta, Mutek, Channel Master/CDE, Hirschmann and our own exclusive aerial ranges for various VHF options. WHETHER YOUR NEED IS FOR LOCAL OR FRINGE RECEPTION, ALTERNATIVE CHANNELS, TV/FM DXING, OR FOR A DISTRIBUTION SYSTEM, SOUTH WEST IS THE 'ONE -STOP' ADDRESS FOR ALL EQUIP- MENT. We can offer a 4GHz TVRO satellite terminal package land in addition a 2% metre fibre glass segmented dish suitable to 20GHz) and with 12GHz options available shortly. SOUTH WEST AERIALS IS UNIQUE - TRY OUR 1983 COMPREHENSIVE CATALOGUE AT 54p. Please include an SAE with all enquiries, customer reception consultancies and for our own VHF aerial leaflets. (Access/Barclaycard welcome). TV LINE OUTPUT TRANSFORMERS If the Transformer you require is not listed please phone. RANK BUSH MURPHY Z146 A640 dual std mono 1.51 Bush A792, A793 single std mono 8.51 A774 single std mono 8.50 A816 solid state mono 9.00 Z712 T16a T16b mono portable 9.00 A823 A823b A823av colour Z179 Z722 series colour Z718 18" series Z718 20" 22" 26" series T20a T22 series colour G.E.C to to "GAIETY" FINELINE IX 2114 portable mono M1501H portable mono 8.00 DUAL STD hybrid colour SINGLE STD hybrid colour SINGLE STD solid state or 110 FERGUSON HMV MARCONI mono mono i'w mono series mono EHT or SCAN 7.94 ADD 15% VAT to AU. prices. Tidman Mail Order Ltd., 236 Sandycombe Road, Richmond, Surrey. Approx. 1 mils from Kew Bridge. Phone: Mon -Fri 9 am to pm to 4.30 pm. Sat 10 am to 12 pm. DECCA M mono 8.00 MS mono portable 9.13 GYPSY portable 9.13 CS colour 8.00 CS colour 8.00 '30' series BRADFORD colour series colour series colour 8.00 PHILIPS series mono series solid state mono 8.50 G8 series colour too G9 series colour 8.50 Gll series colour KB4TT VC200 VC205 VC207 mono 8.00 VC300 VC301 VC302 portable 8.00 CVC1 CVC2 colour 9.00 CVC5 CVC7 CVC8 CVC9 colour 9.00 CVC20 series colour 9.00 CVC30 CVC32 series colour 8.00 CVC40 series LOPT TESTER Total Price Hamond Components (Midland) Ltd., 416 Moseley Road, Birmingham B12 9AX. Phone: Mon -Fn 9 am to 1 pm. 2 pm to 5.30 pm. TELEVISION APRIL

42 i'i'.111:4.-- Left: Eurikon DBS test identification logo, unscrambled. Centre: The same signal but this time scrambled. Photos from A. Wiese. Right: Test pattern received from the Ederkopf WDR transmitter on ch. E50. Photo courtesy Ryn Muntjewerff. indicate that tests are in progress. Some of the tests were by chance transmitted from Rowridge, Isle of Wight. In brief: In addition to the TSS-1 transmitters being established in E. Germany (see last month) we understand that several TSS outlets have been set up in Czechoslovakia to serve the Russian army - total so far three... The NOS (Dutch) and RTB-F (Belgian) ch. E3 transmitters are to stay in operation for some time... A 50MHz Thorn Part No. 00E8 -t93 -RBI (safety component) TV tuner IF output 6Bp 4kV ceramic disc L2...NNScreened housing Fig. 1: Circuit diagram of the sound converter. t2v 10mA stabilised To VHF radio receiver IF strip amateur beacon (GB3SIX) is in operation 24 hours a day on Anglesey, beaming west. It was received in Hartford, Connecticut at 1700GMT on December 31st. Receiving MHz Sound Robin Crossley's tunable sound i.f. circuit, featured in the January column, proved of interest to readers. The Benelux DX Club has since sent details of a converter devised by Piet Jansen (Rotterdam) and Gerard Boerema (Eindhoven). The circuit is shown in Fig. 1: it's relatively simple, using a bipolar transistor and a dual -gate f.e.t. The AF124 transistor oscillates at around MHz, its output being coupled to one of the gates of the f.e.t. The i.f. signal from the TV receiver's tuner is coupled via C10 and an external capacitor to the other gate. The output, at around 102MHz, is developed across L4 and coupled by L5 to an f.m. tuner/radio receiver which acts as a variable tuned i.f. strip. The board layout is shown in Fig. 2, and it will be seen that the two main coils Ll and L4/5 are printed. Alignment is simple, though a local TV transmission is required. Couple the input from the TV tuner to the converter and adjust Cl and C8 to 5pF. Sound should be heard from the f.m. radio receiver. Fine adjustment of Cl will give the correct output at MHz. C8 provides final peaking. Once set up for say a 6MHz intercarrier sound signal, tuning the receiver up or down by 0.5MHz will provide reception of the other standard sound spacings. Note that the components used to couple the tuner's output to the converter must be correctly rated for safety reasons. Our thanks to the BDX Club for permission to publish these details. 12V supply Output to VHF radio receiver (b) Fig. 2: Printed board pattern and component layout for the sound converter. 320 (a) IF input from TV tuner TELEVISION APRIL 1983

43 Service Bureau Requests for advice in dealing with servicing problems must be accompanied by a E100 postal order (made out to IPC Magazines Ltd.), the query coupon printed below and a stamped addressed envelope. We can deal with only one query at a time. We regret that we cannot supply service sheets nor answer queries over the telephone. THORN 3000 CHASSIS There's lack of width, about two inches at each side of the screen, and the voltage across the beam limiter resistor R907 is high at 3V instead of about 1.5V. A new tripler has been tried without improving matters. Try removing the shift choke L504 from the timebase panel. If normal operation returns, this proves that L504 has shorted turns. If the fault persists, it's likely that either the line output or the e.h.t. transformer has shorted turns. Unfortunately substitution of T503 and T504 is the only way to determine which one is responsible. SONY KV181OUB There's lack of height at the top and bottom, with flyback lines at the top and thick bright lines across the centre. Sometimes the picture flickers and normal operation is restored for several days. The faults then return. I've tried replacing the coupling electrolytics in the field timebase circuit. The main suspects are the output stage emitter decoupler C523, the output transistors Q503/4 and the driver transistor Q502. Substitution is the only sure check. First however flex and tap the panel to ensure that dry - joints or similar faults are not to blame. BEOVISION 3400 CHASSIS Intermittent loss of field scan was followed by complete loss of vision and sound. The trip resistor 2R143 in the 1.t. regulator circuit was found open -circuit and the series regulator transistor OTR8 turned out to be faulty. Putting these matters right restored the vision and sound but with the 32V line at about 40V and no regulating action. It appears that OTR8 is being turned hard on. If your replacement is correctly wired and intact, the driver transistor 2TR28 has probably been damaged. A less likely cause is the error detector transistor 2TR27. Ensure that the negative output from the bridge, at 2R140, is not earthed due to a solder blob or trapped wire to OTR8. GRUNDIG 5011 There's a tuning fault. Only channel two works, with perfect sound, picture and colour. When the touch pads for any of the other channels are touched there's a heavy hissing sound and the picture shrinks. First thoroughly clean the touch pads with methylated spirits in case there is any conductive deposit around the number two selector. R312, which is in series with the channel two selector, can be disconnected to prove the point. Alternatively R312 could be noisy - try swapping it over with one of the other series resistors as a check. If these actions fail, it's likely that IC222 (SN16861NG) or IC221 (SN16848N) in the channel selector circuit is faulty. DECCA 30 SERIES CHASSIS When the set is first switched on the picture appears with light and dark vertical bands at the centre. These tend to expand across the screen and reduce in intensity after a minute or so, leaving a normal picture. After about a quarter of an hour however the red and green convergence for some three inches at both sides of the screen goes quite suddenly. The relevant convergence controls don't seem to be in distress. The central striations may be due to failure of one or other of the line output stage valves - PL509 and PY500. If these prove o.k., check the line output valve's screen grid decoupling capacitor C432 (0.1µF) and the boost capacitor C436 (should be 0.22µF). The RG line convergence problem should respond to replacing the clamp diode D412 (Y933) and checking for hair -line cracks or dry -joints on the convergence panel in the vicinity of the RG line tilt coil L417. THORN 1590 CHASSIS There's a comprehensive field fault - rapid rolling, bottom foldover, poor linearity, flyback lines and a one inch black band at the bottom. Normal results are obtained when the meter is connected to the base of VT15, one of the transistors in the field multivibrator circuit. Reducing the value of the cross -coupling capacitor C71 from 0.22µF to 0.18µF also provides a cure. The two transistors in the field oscillator are suspect and their forward and reverse resistances should be checked. Then check the values of the resistors in the hold control circuit, particularly R79 (120k11). TELEFUNKEN 709 CHASSIS To start with the screen is bright with no picture. Some minutes later there are black flashes across the screen, then the picture appears. The sound is not affected. On one occasion the picture came up immediately but was later lost for about ten minutes. It will be necessary to check through the luminance channel, starting with transistor T104 in the i.f. unit. The very small choke (L140) in this transistor's emitter circuit has a habit of going open -circuit - check this for intermittency. Check the plugs and sockets where the luminance signal goes off to the brightness and contrast controls - if loose, these can cause loss of signal. Transistors T611 and T612 have been known to have loose leads iprnommumumuni I II III II M QUERY COUPON Available until 20th April One coupon, plus a E180 (inc. VAT) postal order, must accompany EACH PROBLEM sent in accordance with the notice above. iii TELEVISION APRIL 1983 N iiimomommummimminammulll TELEVISION APRIL ii I II II II III

44 due to poor soldering. The delay line can also be badly soldered. THORN 3000 CHASSIS There's a vertical bar which is 02in. wide and 0.8in. from the right-hand edge of the screen. The bar is patterned, the patterning changing in a random manner. There's no degradation of the picture to the right of the bar, which seems to be more of a hiccup in the flyback than foldover. IL RIO I CASE 244 Each month we provide an interesting case of television servicing to exercise your ingenuity. These are not trick questions but are based on actual practical faults. THE CURRENT mini -boom in the sales of personal computers and the advent of breakfast TV have, in this part of the world at any rate, resulted in a steady demand for second sets. Where the customer can afford a new small -screen receiver, either colour or monochrome, the sales department gets the benefit. Very often however a refurbished set at a low price is required: our service department now has a flourishing trade in "bargain basement" sets - ex -rental and trade-in models that have been overhauled, titivated and are marketed by our versatile engineer/salesmen John. For inexpensive small computers such as the Sinclair ZX81 the ideal monitor is a 20 in. monochrome set with a picture tube in good condition - the characters and graphics are small, and call for a set with good focus capabilities. We favour ITT sets fitted with the VC200 chassis for this application, and whilst preparing a batch of these sets for a school John came across an SV054 with a ballooning picture. The raster was of the correct size at very low beam current, but the slightest brightness increase made it expand in all directions. At average brightness levels little more than the centre circle of the test card could be seen, bloated and distended. Plainly the e.h.t. regulation was in trouble! The e.h.t. rectifier stick D10 (TV20) is the most common culprit when this symptom is present, so in went a new one. When the set warmed up, the picture was as elastic as before. The line output stage valves, PL504 and PY88, are the next suspects, so a couple of sparkling new ones were fitted - with absolutely no effect on the fault! A new PCF802 line oscillator valve followed them in, once more to no avail, so John settled down with the AVO and circuit diagram to suss out the problem. He established that the width/e.h.t. stabilisation control We suggest you check C514 (4.7µF) which decouples the supply to the line output stage, C515 which decouples the line driver transistor's supply, and make sure that the ferrite beads have not been removed from the line output transistor. In stubborn cases the fault can be minimised by decoupling the supply to the tuner with 0.01µF and 25µF capacitors in parallel, fitted at the tuner. Check that the leads to the tuner are dressed away from the chassis and that a good earth connection exists between the two. Fully advance the r.f. gain control R5. was working correctly, and that the h.t. supply to the line output stage - 240V at pin 9 of the PY88 - was about right. The line output transformer derived 20V 1.t. supply and the boost voltage were present and correct at all settings of the brightness control. John then brewed some tea whilst seeking inspiration. It came in the form of a decision to check the d.c. resistance of the line ouput transformer's e.h.t. overwinding and to confirm the continuity of the e.h.t. leads and connectors. The overwinding resistance corresponded with that of a known good transformer, and there were no breaks or high -resistance contacts in the e.h.t. circuit. What next? The tube's outer conductive coating was then examined: it looked all right, and an ohmmeter check confirmed that it was correctly earthed to the metal chassis. John next hooked up an e.h.t. voltmeter to the tube's final anode connector. What a surprise! The set is now in a neat row with its eleven companions at the local school's lab. What shiny new component does it contain? ANSWER TO TEST CASE page 267 last month - Active filter circuits tend to be taken for granted, but strange effects can arise as last month's puzzle showed. The touble was in a Pye set fitted with the Philips G11 chassis, the symptom being breathing at the sides of the raster due to a 100Hz ripple on the h.t. line. All conventional fault-finding approaches had, it seemed, been exhausted. There's one component in the circuit that does nothing most of the time - the 27V zener diode D4021. It's normally held non-conductive by a bias voltage of some 8V, being included in the circuit simply to protect the filter transistors Tr4032/3 from excessive voltage at switch on. When C4040 and the other smoothing capacitors are discharged, these transistors can be subjected to an excessive voltage surge. At switch on there's zero voltage at the h.t. fuse F4037: D4021 conducts, limiting the voltage across the transistors to about 30V until the normal working conditions are established. In our problem set this zener diode was leaking - like a seive, the technician commented - putting an excessive bias, with superimposed ripple, on the base of the driver transistor Tr4033. A new zener diode restored normality, with the raster sides as straight as flagpoles and the correct 153V at the decoupling capacitor C4040. Published on approximately the 22nd of each month by IPC Magazines Limited, King's Reach Tower, Stamford Street, London SE1 9LS. Filmsetting by Trutape Setting Systems, Northdown Road, Margate, Kent. Printed in England by The Riverside Press Ltd., Thanet Way, Whitstable, Kent. Distributed by IPC Magazines Ltd., Lavington House, 25 Lavington Street, London SE1 OPF. Sole Agents for Australia and New Zealand - Gordon and Gotch (A/sia) Ltd.; South Africa - Central News Agency Ltd. Subscriptions: Inland 11, overseas (surface mail) 12 per annum, payable to IPC Services, Oakfield House, Perrymount Road, Haywards Heath, Sussex. "Television" is sold subject to the following conditions, namely that it shall not, without the written consent of the Publishers first having been given, be lent, resold, hired out or otherwise disposed by way of Trade at more than the recommended selling price shown on the cover, excluding Eire where the selling price is subject to currency exchange fluctuations and VAT, and that it shall not be lent, resold, hired out orotherwise disposed of in a mutilated condition or in any unauthorised cover by way of Trade or affixed to or as part of any publication or advertising, literary or pictorial matter whatsoever. 322 TELEVISION APRIL 1983

45 1000's OF COMPLETE TV'S TUBES & PANEL ALWAYS IN STOCK Give us the opportunity to quote for all your requirements. Mixed loads delivered to your door directly from source - at unbeatable prices plus special discounts for bulk purchases. JUST ARRIVED! Fresh stocks from our suppliers. Call BRAINTREE (0376) hour service AMPLE FREE PARKING G 8's L,f=x5.00 OPENING HOURS BRAINTREE Mon -Fri Saturday 9-6 pm 9-3 pm LONDON Mon -Fri 10-5 pm Saturday 10-1 pm Warners Mill, South St. Braintree, Essex. Tel; (0376) Shacldewell Rd. London N16. Telephone; COMPLETE SUPERB CABINETS MOSTLY SWITCH ONS 8's 22" 5 FOR FOR FOR 410 WORKING SETS 30 SPECIAL OFFER 500 ONLY All prices subject to 15% V.A. T s SETS EXPORT SPECIALISTS AVAILABLE EVERY WEEK -OPEN 7 DAYS Bulk Shipments catered for COLOUR T.V. & MUSIC CENTRE Old Mixon Trading Estate, Winterstoke Road, Weston Super Mare, Avon. Tel: TV LINE OUTPUT TRANSFORMERS FAST RETURN OF POST SERVICE RANK BUSH MURPHY Z146 A640 A774 A816 A792 A793 A823 A823b A823av colour DECCA MS2000 MS mono CS '30' series BRADFORD colour CS series colour REWIND SERVICE available for most continental types i.e. Cuba, Skantic, Luxor, Korting, Tyne, Berry, K80 M. Old Lopt required. INDESIT 20EGB 24EGB mono KB -ITT VC200 VC205 VC207 CVC5 CVC7 CVC8 CVC9 colour CVC20 CVC30 CVC32 series colour PHILIPS 170 series dual std mono series mono COLOUR G8 series G9 series PYE EKCO RV chassis THORN 1600 WALTHAM 125 G.E.C to 2064 dual std mono 2047 to 2105 DUAL STD hybrid colour SINGLE STD hybrid colour PRICES INCLUDE P. & P. & 1 5% VAT COLOUR LOPTS 0.00 MONO LOPTS 8.00 WINDINGS RANK BUSH MURPHY Colour hybrid quadrupler type 720a T22 Z719 Z722 Pry & Sec Z718 series primary Z718 series EHT overwind ULTRA THORN EHT overwind 1590 overwind 1615 winding PHILIPS G6 EHT (exchange basis only) G6 primary PYE691 All lopts and windings are new Open Mon.-Fri. 9 to 5.30 pm Allow 1-2 days for delivery. PAPWORTH TRANSFORMERS 80 Merton High Street London SW19 1 BE to 697 EHT overwind 691 to 697 primary and guaranteed S.A.E. all enquiries Barclaycard and Access welcome ws.,.t& f6.00 f6.00 f7.00 f7.00 f For orders placed at the Post office TransTcash TELEVISION APRIL

46 ELECTRONIC EQUIPMENT SERVICING (TELEVISION/VIDEO) full-time College course TRAINING INVOLVES A HIGH PERCENTAGE OF WORKSHOP FAULT DIAGNOSIS ON MONOCHROME & COLOUR TELEVISION EQUIPMENT. CLOSED CIRCUIT TV & VIDEO CASSETTE RECORDER PRINCIPLES ARE INCLUDED IN THE COURSE 15 MONTHS COURSE for beginners to include Electronic Fundamentals 6 MONTHS COURSE for BSc, HND, CGLI, TEC and similar applicants COLLEGE DIPLOMA AND TEC Next two courses commence on April 25th & September 19th. Also courses in Computers/Microprocessors, and Radiocommunication/Radar leading to College Diploma and Technician Education Council awards. Prospectus from: LONDON ELECTRONICS COLLEGE (Dept 13/4) 20 Penywern Road, Earls Court, London SW5 9SU Tel: rag" p \ \ _ 13 WORCESTER ST., wv2lv4er HAMPTON, Telex: Telepart Pattern Generator Exceptionally light and durable I /'_Pocket size for outside service ^... "_,JI PP3 battery power source Five different test patterns for colour and mono TV Cross hatch grid Dot matrix White raster Horizontals Verticles A lightweight, extremely portable and versatile pattern generator for black/white and colour T.V. alignment and service at the customers home. At the turn of a switch, the generator can provide five essential test patterns for correct installation, fast checks and repairs. Pattern stability is first class and compares favourably with other more costly bulky generators only suitable for bench work. The generator is pocket size measuring 10,.7.5 x4 cm and weighs only 190 grams. PRICE (Subject to V.A.T.) POST & PACKING 1.15 Telepart Colour Bar Generator Exceptionally light & durable ' Compact 13,1 7.5, 5.5 cms Battery powered for mobility Cross hatch grid White raster Grey scale Colour bars Sound A Versatile Generator for Servicing or aligning mono or colour TV receivers. Lightweight and very compact for outside service. Features sound facility often not found on more costly generators. PRICE (Subject to V.A.T.) POST & PACKING 1.15 Power Supply A Power Supply can be supplied for the Telepart COLOUR BAR GENERATOR. This compact unit mounts by 2 screws into the Battery compartment and converts the unit to a bench instrument. PRICE 5.50 (Subject to V.A.T.) Supplied by return, off the shelf COLOUR SETS GALORE Hundreds in Stock. From 20. Guaranteed Complete. Mono's and non -complete sets from 3. Most makes available. QUALITY COLOUR TUBES Reconditioned and used tubes. From 10 Guaranteed. Don't delay, ring today. ALPHA TUBES (DUNSTABLE) 53 Lowther Road, Dunstable. Tel. (0582) TRADE A.B.C. ELECTRONICS Rear of 20, HANKINSON ROAD, WINTON, BOURNEMOUTH. TEL: TRADE TV's BEST PRICES Colour From VAT B&W From VAT DISCOUNT ON QUANTITIES ALL MAKES - ALL SIZES - ALL COMPLETE CALL IN OR RING FOR COMPETITIVE QUOTE FULLY REFURBISHED SETS AVAILABLE + DELIVERY SERVICE 324 TELEVISION APRIL 1983

47 THANDAR PORTABLE TEST BENCH A wide range of high performance instruments, at prices that are hard to beat, puts professional test capability on your bench. COUNTERS -TF20010Hz to 200MHz; TF04010Hz to 40MHz; PFM200A 20Hz to 200MHz (hand-held model); TP600 prescalesto 600MHz; TP1000 Prescalesto 1GHz. MULTIMETERS -TM3510.1% 31/2 digit LCD; TM %31/2 digit LCD; TM % 31/2 digit LED; TM % 31/2 digit LCD (hand-held model); TM %41/2 digit with autoranging and sample hold. OSCILLOSCOPE-SC110A 10MHz, 10mV sensitivity, 40mm CRT with 6mm graticule divisions. THERMOMETERS-TH C to C, 1" resolution; TH C to C and -40 F to F, 0.1 and 1' resolution. Both accept any type K thermocouple. GENERATORS-TG1001Hz to 100kHz Function, Sine, Square, Triangle Wave; TG Hzto 2MHz Function, Sine, Square, Triangle Wave; TG1055Hz to 5MHz Pulse, Free Run, Gated or Triggered Modes. LOGIC ANALYSERS-TA20808 channel 20MHz; TA channel 20MHz. ACCESSORIES- Bench rack, test leads, carrying cases, mains adaptors, probes, Send for our latest catalogue and price list. Thandar Electronics Ltd, London Road, St. Ives, Huntingdon, Cambridgeshire PE174HJ. Telephone (0480) Telex thandar ELECTRONICS LIMITED PUTTING THE BEST WITHIN YOUR GRASP TH12 SPECIAL OFFER SURPLUS STOCK TO CLEAR AC PX N C AC BFY NE AC F N LM A BT M309K AD AD AF AF AU B U L BC BU208A L BC BU L BC BU BC SC BY SC BC BY SC e BC BY SC BC A SC C MB3712A C B C UPC LM BD R LM381A TBA TBA TBA LS TBA VALVES 74LS TBA DY LS TBA ECC LS TBA810S ECC LS ECC LS TBA ECC TBA ECH SOCKETS BD ECH PIN TCA ECLBO PIN TCA ECL PIN TDA ECL PIN BD TDA ECL PIN BD ECL PIN TDA EF PIN TDA EF PIN 0200 BDX EF PIN 0250 BF TDA EY BF1B TDA EY LED BF TIP PC Omm Red BF TIP41A 0220 PCF mm Yellow BF TIP42A 0220 PCL mm Green F TIP PCL mm Red E TIP PCL mm Yellow F PCL mm Green E N PCL BF N PFL ELECTROLYTIC 8E N PL F BFX N P V CAN 0200 Please add P&P and VAT at 15% Govt. Colleges, etc orders accepted Quotations given for Large Quantities Please allow 7 days for delivery All brand.new Components All valves are new and boxed SUNMIT ELECTRONICS 9 THE BROADWAY, PRESTON ROAD, WEMBLEY, MIDDLESEX, ENGLAND. Telephone TV TUBES TUBE POLISHING WORKING TV's WORKING PANELS FREE DELIVERY* Quality, High Temperature Reprocessing Colour Tubes One year guarantee (optional extension up to three years) Two year guarantee (optional extension up to four years) Delta 90 up to 20" up to 22" up to 26" up to 26" (fast heat, narrow neck) In Line & PIL Up to 20" Up to 22" Up to 26" cc19p Please add 12 plus VAT for optional guarantee on any type of colour tube. MONO TUBES (One Year Guarantee) A50-120W/R 12, A61-120W/R 13, Mono Portables 16 All tubes exchange glass required. FOLOWING ITEMS CALLERS ONLY Solid state working colour N's, with well view tubes fitted 11 year guarantee on tubes) from Only 45 Working TV Panels at Reasonable Prices Your good, working tubes with scratches or small chips, can be POLISHED with our purpose built polishing equipment. Only 7 per tube. Delivery Service up to 40 miles from Luton. Fixed Charge 3. 'Free Delivery for tube orders over 50 + VAT. Please add 15'o VAT to all prices. Callers welcome. Please phone first. Send for a fully comprehensive price list and a wall chart of approx 1700 Colour Tube Types that can be processed by us. WELL VIEW Mis.dland Rd. Luton, Bed Open Mon -Fri 8ant-6pm, Sat 9am-5pm. Tel Your Local Tube Stockist: Retach Ltd., Northwood, Middx. Tel West One Distributors Ltd., Gt. Missenden, Bucks. Tel Rushden Rentals Ltd., Rushden, Northants. Tel Davenry Rentals, Daventy, Northants. Tel S.S. TV Services, Bradford, Yorks. Tel Please note that we have no connections whatsoever with any other business having similar name to ours. TELEVISION APRIL

48 T.S.R. REBUILT SPECIALIST C.R.T.s Specialist C.R.T.s rebuilt at our new Scottish factory include: - All SONY C.R.T.s and PROJECTION SYSTEMS. All HITACHI C.R.T.s including the 560DZB22 and 510VLB22 series. All IN -LINE C.R.T.s what ever make. All MONITOR C.R.T.s. All GAMING MACHINE C.R.Ts. For further details contact the following Sole Distributors. Double D. Distributors, 27 Florence Road, Parkstone, Poole. Dorset. Tel: (0202) Express T.V. Supplies, 33 Fortescue Lane, Rugeley, Staffs. Tel: (08894) P. E. Tubes (Northern Ireland Ltd) Artillery Road, Coleraine, Co Londonderry. Tel: (0265) Torbay Tubes, 2A Barton Hill Road, Barton Industries, Torquay, Devon. Tel: (0803) K. C. Wholesalers, London. Tel: B and E Electronic Supplies, 1 Maurice Road, St. Andrews, Bristol. Tel: (0272) Information on all other C.R.T.s available on request. Sony, and Hitachi DZB/VLB glass bought. T.S.R. Vacuonics Ltd., Tom Stewart Lane, St. Andrews, Fife, Scotland. Tel: (0334) Radio Supplies (Components Ltd) P.O. Box 27, 39 Whitby Street, Hartlepool, Cleveland. Tel: (0429) TOP TWENTY T.V. SPARES 1. Philips G8 LOPTX (genuine Philips) Decca 30 Series LOPTX (genuine Decca) Decca 100 Series LOPTX (genuine Decca) ITT CVC 25/30/32 LOPTX (genuine ITT) 5. Pye 713/725/731 Vis Gain Module (replaces expensive ) 6. 5 x Universal Aerial Socket Kit 5.50 (replaces most UK and Continental skts) x BU x BU208A ITT CVC 5/8/9 EHT Tray Grundig 5010/5011 EHT Tray Decca 1730/1830 Doubler Decca 80 Series EHT Tray GEC 2040 (Hybrid) EHT Tray X BY127 Diodes Thorn 1500 (5 Stick) EHT Tray Thorn 8000 Doubler 17. Thorn 1400 EHT Tray Thorn 1690/91 LOPTX Philips G9 EHT Tray ITT Universal EHT Tray 5.25 All components are Al quality from prime manufacturers, and are dispatched by post same day as order received together with any refund due. All goods should be delivered within 4 working days. Please add 15% VAT and 90p P & P QUICK SAVE T.V. SPARES Muxton House, Muxton, Telford, Salop. REG. OFFICE ONLY CALLERS STRICTLY BY APPOINTMENT UK ONLY DECCA 18" 20" 22" 26" PHILIPS G8 22" 26" PHILIPS " PYE CT200 18" PYE CHELSEA 18" NAT. PANASONIC 18" TVs TVs TVs PANELS PANELS PANELS from 825 from (25 from 835 from E35 from En POA BUSH A823 22" 26" HITACHI 18" THORN " 22" 26" THORN " ITT CVC8 22" from E25 POA from E25 from E30 from E40 The above prices are for working TVs, Non workers usually available Please ring for prices. QUANTITY DISCOUNT FOR 10+ Panels for most makes available with 3 month guarantee. Add f'1.70 per panel for postage + 15% VAT (Also see NJ. Electronics advertisements, at your TV spares panels etc. under one roof). CONTRAST U.K. 82)53/04 STORFORTH LANE TOG. EST. CHESTERFIELD, DERBYSHIRE 041 OSW Tel. Chesterfield (024) THE NO. 1 SOURCE IN THE SOUTH GOOD STOCKS OF MODERN COLOUR UNBEATABLE PRICE AND QUALITY DON'T DELAY RING TODAY TELETRADERS ST. LEONARDS WAREHOUSE ST. LEONARDS ROAD, NEWTON ABBOT, DEVON Telephone: (0626) TELEVISION APRIL 1983

49 N7128 COLOUR BAR GENERATOR New improved design with additional features. * Six Standard Test Patterns viz. Colour Bars, Red Raster, Linear Grey Scale, Cross Hatch, Dots, White Raster. * All monochrome patterns available with or without burst signal (for checking colour killer action etc). * Crystal controlled sub -carrier, Line and Field frequencies. * Three outputs to rear panel: Video at 1N/ P to P into 75ohm, 800Hz (approx), sine wave audio and modulated UHF (VHF available) 4mV at 75ohm. * 6MHz (adjustable to 5.5MHz) intercarrier sound. * Front panel LED to indicate "Power On". * Integral re -chargeable ni-cad battery plus mains unit/charger. * Fully built, tested and guaranteed for 12 months. PRICE N7118 COLOUR BAR GENERATOR KIT * Five Standard Test Patterns viz. Colour Bars, Red Raster, Linear Grey Scale, Cross Hatch and White Raster * Crystal controlled sub -carrier, Line and Field Frequencies. * UHF Output (VHF available). * Integral Ni-cad Battery and mains unit/charger. * Optional integral sound and video board add-on kits Still available at special price Please add 15% VAT postage and packing per Generator. INTRACEPT ELECTRONICS LTD., 203 PICTON ROAD, LIVERPOOL L15 4LG. TEL: BOOK NEWS FROM NEWNES DOMESTIC VIDEOCASSETTE RECORDERS S Beeching A Servicing Guide Written for the service technician by leading technical authority This book takes the subject from basics and then shows later modifications to the techniques, giving examples of various manufacturers' approaches to the subject. Includes VHS, Betamax and Grundig and Philips V2000 systems pages SERVICING MONOCHROME PORTABLE TELEVISION G R Wilding Faults and probable causes listed. Covers British, Japanese and European sets This dual purpose book explains the circuitry of current standard, miniature and 'combi' monochrome portables, together with typical faults and probable causes, and contains full size reprints of British, Japanese and Continental manufacturers' circuit diagrams and service information pages ORDER NOW from your local Bookseller. [ewnes Technical Books Borough Green. Sevenoaks Kent TN15 8PH an,rnprint of Butterworths CENTREVISION NO. 1 IN WALES 9000 Sq Ft CTV * MITSUBISHI CTV 22 * KORTING CTV 14 + VAT * HITACHI CTV FROM 28 + VAT * THORN " 40 + VAT * RANK Z719 -Z718 -T20 VARIOUS PRICES * PHILIPS " REMOTE 35 + VAT * GEC SOLID STATE FROM 28 + VAT * THE TRADE SAY THE BEST QUALITY SETS ON THE MARKET TODAY * BULK TERMS TO OTHER WHOLESALERS DECCA 30 SERIES 22" IN 10'S SELECTION OF WORKING SETS ALSO VIDEO IN STOCK DONT DELAY PHONE TODAY CENTREVISION HOUSE, SLOPER ROAD, CARDIFF CF1 8AB. TELEVISION APRIL

50 WE HAVE LARGE STOCKS OF ALL MODELS IN EVERY DEPOT ON OFFER Contact our Branch ManageronThe Hot -Line Number FOR EXAMPLE: 26" THORN Trade Workers 19" THORN 8500 Trade Workers 0Mb O.* C /26" Philips GI:1'0ff the pile' C 7.50 SPECIAL OFFER; THORN9000/PHILIPS G9 GEC Solid State: ALL AT NEGOTIATED, LOW, LOW PRICES! Thousands of Bargains! YOU WILL You must pay us a visit! NOT BE DISAPPOINTED ENGLAND -FL LONDON Contact Tony Nobel Road. Eley Estate Edmonton London NIB NorthCircuLar Road Tel (01) MORLEY Contact Vera Wray Ebenezer Chapel Fountain Street Morley Junction 28M62 Tel (0532) BRADFORD Contact KenTarran 1043 Leeds Road. Thombury Roundabout Bradford 3 Lt nk Motorway M606 FrornM1 M62 Tel (0274) Telex: 'THdex G WARRINGTON Contact Frank 21 Ravenhurst Court Risley Road Birchwood Wamrxron Junction1111/182 Tel (0925) JVC 20" PILOTS IN QUANTITY from 20 each! WALES Contact Nick Wyatt Bulwark Ind Estate Chepstow Nr Bnsto' Junction 22 M4 Tel Chepstow, ;02912)6652 SCOTLAND Contact Fraser Hunter Peacock Cross industrial Estate Bumbank Road Hamilton Off M74motorway Tei (0698) 28214, COLOUR TV SETS PYE CHELSEA PHILIPS G8 520 PHILIPS G8 550 PYE 222 I.T.T. HYBRID DECCA 30 SERIES G.E.C. THORN 8000/8500 THORN 3500 WORKING PI PI Many others including Mono and Japanese. Non workers in most types available at low prices. All prices subject to V.A.T. at 15% QUANTITY DISCOUNTS DELIVERY BY ARRANGEMENT PANELS, STANDS, AERIALS, EX EQUIPMENT TUBES AVAILABLE. N.G.T. REBUILT TUBES First independent rebuilder with B.S.I. CERTIFICATION DELIVERY 5.00 U.K. MAINLAND. NO EXCHANGE GLASS REQUIRED ON DELTA TYPES. SOUTHBRIDGE TV CENTRE 120 Selhurst Road, London SE25 6LL. Tel: HIGH GAIN AERIAL BOOSTERS B45 H/G UHF Television - Tunable over the complete UHF band. Gain above 20dB, noise 2.8dBs. B14 - Band 3 VHF Television - Tunable over the complete Band 3 (Channels (E) 5 to 13). Also covers Aircraft & 2 meter Amateur Bands. Gain above 2 8dBs. Noise 2.8dB. PRICE each AERIAL AMPLIFIERS Aerial amplifiers can produce remarkable improvement on the picture and sound in fringe or difficult areas. B45 - For Mono or Colour this is tunable over complete UHF television band For stereo or standard VHF/FM radio for VHF television band 1 & 3. All amplifiers are complete and ready to use Battery type PP3 or 8V to 18V DC next to the set type fitting. PRICES 6.70 each. AERIAL SPLITTERS 2 way T -TYPE p.70 each Goods despatched on receipt of order. All Prices Fully Inclusive. P & P per Order. SAE.. for Leaflets. Access Cards. ELECTRONIC MAILORDER LTD, 62 Bridge St, Ramsbottom, via Bury, Lancs. BLO 9AGW. Tel Rams ( ) M W ELECTRICAL BROOK PARK AVE. (OFF MARINE RD.) PRESTATYN "WE DO NOT BOOST TUBES" COLOUR TV'S COMPLETE FROM TRADE WORKERS FROM MINIMUM OF TEN G8, DECCA, BUSH, THORN. ALSO MONOs ETC. NEW & GRADED TVs ALSO AVAILABLE OPEN SAT MORN, LATE NIGHT THURS 8pm TEL: PRESTATYN (07456) 89849/ TELEVISION APRIL 1983

51 Well done Scopex Report on the Scopex 14D -10V oscilloscope "I experienced no jitter whatever, and discovered an inherent virtue of digital delay that no analogue delay system has. %V ail a jitter* signal such as comes from any mechanically reproduced video recording system, i.e. tape or disc. the counting system relies on the line numbers rather than the time, so that jitter -tree traces arc produced even after a delay of almost a tali held. In tact the ten -turn vernier delay control, which is fitted with a locking device. is so stable and accurate that I found it possible to set it for a certain line number and come hack two days later and find that same line would he reproduced on a different transmission and at a different room temperature,' The large screen, mains operation and the facilities it offers make it ideal for TV, video, test and much digital work. Technical colleges, polytechnics and similar establishments should also find the I 4D -10V of interest-man of them have to work with a very restricted budget these days, and for demonstrating modern TV techniques this instrument is very useful", " I can wholeheartedly recommend it, not only for its intrinsic virtues but as a piece of British innovation in a field which is being steadily encroached upon by the Oriental big boys. Well done Scopex!" Test report by Eugene Trundle Television January VAT JCO'EX `)( `Y.)t Jr, (-! 'p` k -I( H.11(iI f 1-17 EMO - EUROSONIC - GRUNDIG - TELETON + ALL BRITISH MAKES ETC., ETC. ALL SPARES READILY AVAILABLE IMMEDIATE CREDIT AVAILABLE-TRADE ONLY If you are a trader simply phone for the part you require and we will send it - no quibble - no hold up for status check. Satisfy us over the phone that you are a trader and we will supply almost any TV component by return "off the shelf'. e.g. LOPTX - EHT trays - droppers - OSC coils - switches - cans - smoothers - I.C.'s, etc. etc. YOU CAN BE 95% SURE WE CAN SUPPLY ANY TV COMPONENT BY RETURN IF YOU NEED SPARES FAST- RING NOW! T fob ACCESS AND BARCLAYCARD ACCEPTED. owton) THE TELECENTRE, WORCESTER ST., WOLVERHAMPTON ( APOLLO HIGH TEMPERATURE PUMPED COLOUR TUBES Fast Mail Order service to any part G.B. Delivery 2-3 days. Just phone for a quotation. Delivery Manchester area free same day. Two year guarantee. Fitting while you wait or in your home 20 extra. Also P/L types & Toshiba. 18" A x 343 x " A49-120x/192x " A51-220x/110x " A56-120x/123x/140x " A63-120x x A66-120xA67-120x/140x/ " Bush all transistor colour TV's fully serviced 59 inc. delivery or with (new tube guaranteed 2 years) 89. Philips Video Spares Available hour answering service. 43 Clarke Cres, Little Hulton, Nr. Manchester M28 6XM. LONDON'S LARGEST TELEVISION WHOLESALER... with over 41 thousand sq. feet. "TELEMANN" 8-10 RHODA STREET, (Off Bethnal Green Road) LONDON E.2. FREE CAR PARK TEL: ALL MAKES IN STOCK AND GUARANTEED COMPLETE PYE 22" COLOUR FROM 7.50 PHILIPS 22" G8 (Teak cabinet) PARCEL OF TEN 12 MONO DUAL STANDARD 2 - SINGLE STANDARD 5 FREE DELIVERY TO THE LONDON AREA! TELEPHONE NOW! TELEVISION APRIL

52 *..***.***.****.****.****...**..***.****** MANTEL * * * Manchester's No. 1 in Ex -Rental TVs * * Over 2,000 TVs in stock 4( Special Offer on Working Colour TV's * Ali sets are Serviced with repolished Some Examples of UNTESTED TVs * 1" At7 cabinets ready for sale available Philips G8 550s 22/26 45 Thorn 10 for 125 Philips 18" 40 Philips 6 for 90 * Philips G8 520s 22/26 35 Bush 6 for 80 GEC S/State from 35 GEC 6 for 60 Thorn 17" Decca 6 for 60 Decca 30 18/20/22/26 30 Mono TVs avail. s/s 4 each Japanese from 30 New TV trolly stands. Many other makes available from All sizes All Prices subject to V.A.T. Discount on quantity Ex Equipment Panels & Tubes Available Deliveries may be arranged to the North and Scotland. Ring for quote. Callers welcome. * 419 earlowmoor Road, Chorlton, Manchester 21 2ER. Tel: TELEVISION TUBE SHOP LTD BRAND NEW TUBES AT CUT PRICES A31-19W/20W A OW/3 00W A /51 OW A W/510W A W A OW/1 70W A OW/R A W/R A W/R AGP OAB4/C Some Rebuilt Japanese & European Types Available from VAT DB4CT DB4/240AB4A CT507 equiv DGB4/DMB EUB EUB4A EYB FXB OGNB4A HCB AB AYB AXB RB4/CB4 / AHB RIGONDA 6" COLOUR TUBES (NEW & MULLARD/THORN COLOREX)* 12VARP A OX AB A56-410X A X A56-500X/510X A47-342X A63-120X A47-343X A66-120X A X A66-140X/410X A51-161X A66-500X/510X A OX A OX A51-500X/510X A67-140X/200X A51-570X A67-150X *Old Bulb Required for 110 Colorex* ADD 15% VAT TO ALL THE ABOVE PRICES. ALL TUBES TESTED BEFORE SALE & FULLY G ARAN.' EED TELEVISION TUBE SHOP LTD 52 BATTERSEA BRIDGE RD., LONDON, SW11. Tel / CARRIAGE: Mono 3, Colour 10. r Easy to build projects For everyone earfgaapr p /Motorists, musicians, householders...just some of the people who can benefit from EE's comprehensive, easy -to -follow plans for electrical equipment. Areas covered by EE include: Personal Computing, Motoring, Music, Home Security, Test Gear, Games and Disco. ADD-ON AMPLIFIER FOR ZX SPECTRUM - for use with Sinclair Personal Computer RANGER. SOUND. EFFECT -for guitar, voice etc.: NOVELTY EGG TIMER CAR -RADIO BOOSTER -20w. mono TELEVISION APRIL 1983

53 "TUBE REPLACEMENTS" OFFER SPECIAL TRIAL PRICES "WELLVIEW" EXCHANGE COLOUR A44-271X 24 A47-342X 24 A47-343X 26 A49-120X 24 A51-110X 24 A51-110LF 26 A55-14X 28 A56-120X 28 A63-120X 33 A66-120X 33 A66-140X 33 A67-120X 33 A67-150X 33 If no exchange glass 4 extra "WELLVIEW" EXCHANGE MONO A WR A47-26 WR A WR A WR A WR A NEW A NEW If no exchange glass 1 extra All above plus 15%. Carriage 5.00 inc. VAT. ALL TUBES 18 MONTHS GUARANTEE COLOUR SETS Complete G8's and Pye CT200's 15 + VAT. Others from 10. ALSO YOUR VALVE SUPPLIER NEW AND BOXED (inclusive of VAT) DY802=74p EF 184=64p PC L82=78p PFL200=f1.15 PY800=70p PL ECC81=64p ECC82=64p PC L84=92p PC L86=97p PL508= EF183=78p PC F802=98p PC L805=97p PL504=f1.38 PY88=70p PY500A = 1.82 NEWSFLASH 5 inc. VAT Postage and Packing per valve. All orders over 10 Free of charge. Camping - Self sufficiency - Emergencies Be prepared! 24v transistor fluorescent ballast units will run 2 x 4ft tubes and draw under 2 amps (Philips) 5 each + 75p VAT, p&p 70. Dynamo torches complete with spare bulb. You need never buy torch batteries again. 2 for fi inc. VAT, p&p. Allow up to 14 days for delivery. TUBE REPLACEMENTS Unit No. 1, Monmouth St., Bridgwater, Somerset. Tel Tomorrows Television Today A HANDBOOK ON SATELLITE TELEVISION RECEPTION =MI Receive Satellite Television at home now. Low Noise Amplifiers, Down Convertors, Receivers, Dishes & Feeds explained in detail. Full information on Television Broadcasting Satellites over Europe. Complete listing of more than 20 T.V. Channels on these Satellites. A5. 1. Fully Illustrated 9.85p + 65p p & p YOU COULD BE WATCHING SATELLITE TELEVISION TODAY Please send me copies of Tomorrows Television Today. I enclose cheque for NAME ADDRESS Post to: M. Stone, 47 Filton Avenue, Horfield, Bristol 1983 PRICE LIST DISPLAY ELECTRONICS GOLD LABEL COLOUR TUBES 2 YEAR GUARANTEE 90 up to 19" up to 22" up to 26" 39 The above prices are for standard 38mm Delta Gun Types. Add 5 Gun surcharge for 20AX Types. Other in -line & P.I.L. Types, prices on application. GOLD LABEL MONO TUBES 2 YEAR GUARANTEE 19"/20" 12 23"/24" 14 GREEN LABEL COLOUR TUBES 12 MONTHS GUARANTEE 90 up to 19' up to 22" up to 26" 34 Green Label Prices apply only to standard 38mm Delta Gun Types. They will be of particular interest to customers refurbishing ex -rental sets. BUDGET CORNER Buy any 5 mixed types take 20% discount. Buy any 3 mixed types take 10% discount. Budget prices apply only to colour tubes. The mix can include Gold & Green Label Types if required. PRICES EXCLUDE V.A. T. CALLERS WELCOME Late night Thursdays until 8 p.m. Saturdays until Midday N.B. Customers intending to collect orders are requested to telephone in advance:- even popular types may be out of stock for short periods. UNIT 1 SWAN WHARF WATERLOO ROAD UXBRIDGE MIDDLESEX Telephone: UXBRIDGE TELEVISION APRIL

54 SETS & COMPONENTS 41 6 to * TELEBEST * We specialise in quality working sets only. Trade enquiries only Philips + Thorn 22" From 30 incl. VAT. Discount on quantity. Romford Road, Manor Park, P k London E.12. Tel: ID , GRUNDIG, NORDMENDE, complete sets, circuits, reconditioned panels. Oscilloscope other equipment TRADE TV's For the best quality at the cheapest prices in Nottingham. CASTLE TV 100s of ex -rental sets in stock. S/S colour from S/S mono from 3.00 TV Sales & Spares to the Trade. 346 Radford Road, Nottingham. Tel. Mr. Atkins Nottingham DEGAUSSING COILS. Professional stick type delivered. See U -VIEW T.V. TUBES Panel. Tel: Northwood (Middx) Rear 78 High St., RETACH LTD. Northwood, Middx. COLOUR TV's Complete Set PHILIPS G11 75 REBUILT COLOUR TUBES 20" E year Guarantee. 22" E year Guarantee. 26" year Guarantee. All price + VAT Callers by Appointment TUBE RE -GUNS 2 YEAR GUARANTEE inclusive Also at 30 A A49-191, A44-271, A47, 342 or 3. A66-120, 140, 410, A inclusive. SLIGHTLY USED TUBES A56-120, A A month guarantee IN -LINE RE -GUNS 48 inclusive , , and many more with 1 year guarantee. PROFESSIONAL STICK DE-GAUSSING-COILS EACH INCLUSIVE & DELIVERED 1 Year Guarantee. No need to spend 5 returning old glass if you buy from us (except in -line). Tubes delivered and insured within a few days of receipt of cheque. 5 delivery per tube, 2 for 9 including Scotland and N. Ireland. Discounts for more than 2. U -View (Tubes) 29 Warmsworth Road, Doncaster, Yorks DN4 ORP Open 7 days Callers ring first. 841 TtE A111 No other consumer magazine in the country can reach so effectively those readers who are wholly engaged in the television and affiliated electronic industries. They have a need to know of your products and services. The prepaid rate for semi display setting 5.64 per single column centimetre (minimum 2.5 cms). Classified advertisements 33p per word ARE YOU OVERSTOCKED? Turn your surplus stocks into cash 500,000 AVAILABLE for any surplus electrical stocks ie. TV's, Video's, Washers etc. Phone in strictest confidence: Mr R. Walker, Brighouse (0484) SPARES, PANELS T1/. v. AND MANUALS PHILIPS GRUNDIG TE LEVI EW , Acton Lane, London W.4. TESTED G8 PANELS, I.F Chroma 6. Power supply 6. Tuner series triplers 3. Focu units 2. Control knobs each. SAE other items. McHUGH, 16 Copperkins Road, Hednesford, Staff, WS12 5NW. COLOUR TVs WORKING DECCA BFD TELPRO from 24 ETC. THORN 8500 THORN 3500 PHILIPS G8 FLAP ETC. from f29 Please send for details: 123 Palmerston Road, Boscombe, Nr. Bournemouth, Dorset Tel: TVDX/SATELLITE EQUIPMENT VHF to UHF Converter. 12v supply required. Ideal way to start DXing Band I/II Mosfet mains preamplifier. High gain, low noise (Bill available). SOON TO COME complete 4GHz LNA/downconverter for satellite reception 200 (approx.). SAE data lists: H. COCKS Cripps Corner, Robertsbridge, Sussex TN32 Telephone SECOND HAND COLOUR TV SPARES and tubes, most makes. Telephone Southport (0704) Anytime. CAMPBELL ELECTRONICS LTD. COLOUR T.V. PANEL EXCHANGE/ REPAIR SERVICE THORN, RANK, PHILIPS, GEC, DECCA, TELPRO, GRUNDIG etc. 90 Day Guarantee on all repairs - same day postal service. Telephone Telford (0952) for catalogue and price list. CAMPBELL ELECTRONICS LTD., Unit 5, Heath Hill Estate, Dawley, Telford, Shropshire. VISIONTEL A NEW NAME IN TELEVISION TRADE Ex rental colour TV's from 10, B&W from 4. Due to our new contract we are now able to offer you the best quality and a big selection of ex rental TV's at very reasonable prices. Our range consist of Thorn 3000, 3500, 8000, 8500, 8800, 9000; Philips G8, G9, G11; Decca, GEC, Bush, Grundig, JVC, Saba, Nordmende, ITT & Japanese sets also in stock. Most panels in stock from 4 each. VISIONTEL 55 Kilburn High Road, London N.W.6. Tel TELEVISION APRIL 1983

55 (minimum 12 words), box number 60p extra. All cheques, postal orders etc., to be made payable to Television, and crossed "Lloyds Bank Ltd". Treasury notes should always be sent registered post. Advertisements, together with remittance, should be sent to the Classified Advertisement Dept., Television Room 2612, IPC Magazines Limited, Kings Reach Tower, Stamford Street, London SE1 9LS. (Telephone ). TELEVISION Trade Supplies of Good Quality Colour & Mono TV's. Most Makes available, suitable for Sale or Re -Rent. GENERAL UNION STREET, DONCASTER (0302) FACTORS GOOD MOTORWAY ACCESS TOSHIBA 110 PIL TUBES 20" 22" 26" 20" 510 KGB 22 from 20 22" 560 H B TB AKB22 from 20 26" 670 XB22 from 20 RING JEFFRIES EAST ANGLIA BARRY TV SERVICES Good quality working colour televisions (from 35 plus VAT) straight from our retail shelves, (with good tubes & cabinets). Available at all times - delivery available anywhere. Contact John, Dave or Steve on Cambridge or Ely Your Satisfaction Is Our Concern. BULK BARGAIN T.V. SERVICE PACK Contains at least 50 worth of T.V. service components and accessories. Loads of hard to obtain T.V. spares and components. Ideal for the service engineer. Only 12.50, carr Ref. Guar. HAVE YOU SEEN THE GREEN CAT? 1000s of new components, T.V., radio, and electronic items at unbelievably low prices. Probably the cheapest in the country. Send for GREEN CAT and reserve FREE RECORD SPEED INDICATOR. MYERS ELECTRONICS, Dept. TV2, 12/14 Harper Street, Leeds LS2 7EA. Next to Union Jack Clothing Store, Leeds LS2 7EA. Callers welcome at our NEW retail premises. Open 9 to 5 Mon to Sat. Tel TELEVISION TUNER REPAIRS ALL TYPES BRITISH, EUROPEAN, JAPANESE ETC. MMMMM NMI IMO ION MEN-TU ELECTRONICS, SALTERNS LANE, FAREHAM, HANTS. Tel: CASED ISOLATION TRANSFORMERS 500w max, suitable TV work Working test equipment Meters, P.S.U's etc. SAE lists: S.H.E. 5, S Joseph's Park, Ballycruttle, Downpatrick BT30 7EN. RANK BUSH MURPHY TV PANELS REPAIR/SALE SERVICE BY EX RRI EXPERTS. SAME DAY RETURN WITH 3 MONTHS GUARANTEE. GENUINE RBM TECH- NOLOGY AT YOUR SERVICE. MONDAY TO SATURDAY 9am to 7pm T.K. PANELS SERVICE Tel: ( Bronte Paths, Stevenage, Herts. HAVE MOVED TO WE NEW PREMISES TEST EQUPMEIVT UHF T.V. Pattern Generators Crosshatch & 4 patterns As above but with Greyscale Prices include P&P and VAT. Also available: PAL COLOUR BAR GENERATOR CAPACITANCE METER TRANSISTOR TESTER S.A.E. for prices and full details. The above items are not kits. C.M.J. ELECTRONICS Unit 8, 16 Union Mill St., Horseley Fields, Wolverhampton, WV1 3DW. Tel TURN YOUR SURPLUS capacitors, transistors. etc., into cash. Contact COLES-HARDING & CO, 103 South Brink, Wisbech, Cambs Immediate settlement. Thorn TRIPLERS Thorn 9000 UNIVERSAL' E4 50 I year guarantee The UNIVERSAL TRIPLERcan be used in most G.E.C.. I.T.T.. Pve. Rank. Decca & Continental WING ELECTRONICS 15 Waylands, off Tudor Rd, Hayes End, Middlesex IRISH T.V. DEALERS (No. 1 for s/hand T.V.$) sets to choose from. 2. Most leading makes sold. 3. Fresh stocks weekly. 4. Delivery to any part of Ireland. 5. All sets with VHF/UHF tuners. 6. Colour from only 70 mono from 15. Visit our new spacious warehouse: TELE SPARES LTD. Unit 113 Elm Road, Western Ind. Estate, Dublin 12. Tel: / CLEARANCE SALE LARGE QUANTITY OF GOOD CLASS COLOUR TELEVISIONS BUSH, PYE, GEC, THORN, PHILIPS ETC. Excellent Cabinet Condition. Genuine Change Over TV's and Repossessions. LARGE QUANTITY SOLID STATE BUSH 10 Each (Minimum quantity 5) GEC HYBRID PYE HYBRID MONO 's to choose from!! We export large quantities of TV's weekly. Can we help you? Discount on Quantity Orders. OVER 1,000 MONO N's IN STOCK FROM 's colour tubes suitable for reconditioning. Working colour N's to order ie. Bush 20"/22" 2I.C. excellent picture, ready to sell. Only 39. CALL AND SEE OUR SELECTION WHITE GOODS All types of Washing machines, Vacs, Fridges, Cookers, etc. Hoover Auto's, Servis, Hotpoint, Hoover Uprights, Vacs. 500 always in stock. Fully reconditioned Hoover Twin Tubs and Upright Vacs, all models. Phone for details. PAY US A VISIT AND YOU WILL NOT BE DISAPPOINTED. N.W. ELECTRONICS BOLINGBROOKE STREET (PICKFORD BUILDINGS), BRADFORD 5. 3 minutes from Motorways. Telephone TELEVISION APRIL p.p.

56 SETS & COMPONENTS EX RENTAL C.T.V.'s & REGUN TUBES RBM, THORN, DECCA, PYE GEC, GRUNDIG, ITT, PHILIPS G8, G9, G11, JAPANESE From 10 Also all modules from 4 untested. STARLITE ELECTRONICS, 80 Como St., Romford, Essex. Telephone Romford London Code 3. MONITOR TUBES "GREEN" 12" 110 AW31-550GH MEN-TU ELECTRONICS LTD. SALTERNS LANE, FAREHAM, HANTS. Tel: RANK BUSH MURPHY TRANSFORMERS LINE OUTPUT TRANSFORMERS Z718 (T703A, T706A) (1) New (Complete) (3) Less Focus Module and Rectifier Z718 SPARES (T703A, T706A) Pri , Sec , Rectifier , Lead T20, T22 (T705A) T26 (T7058) Switch -mode Transformers T114 A/B Genuine RBM Units Prompt Postal Service. Add 15% V.A. T. to all Prices. DISCOUNT For QUANTITIES WOODSDALE COMPONENTS MR SKEHAN 34 Field End Road, Eastcote, Pinner, Middlesex HA5 2QT Agents Office, callers by appointment only COLOUR TV PANELS Fully Tested & Working IF CDA Decoder LTB Line Board Frame Board Power GEC * DECCA 13/ BUSH 'A' 5 7* BUSH 'Z' 6 15* * THORN WSW PYE THORN 3/3tK * 08 8* 8 10* 17 6 'denotes exchange panel required If exchange panel not available, please add 5 surcharge. fitted with brand new transformer Post & packing: 1 panel 1.50; 2 panels 2.25; 3 panels Hybrid panels do not include valves. Complete TV's available also most standard sizes CRT's 10 FOR COLLECTION ONLY. LAVITE LTD. Viaduct Mills, Off Savile Street Mfinsbridge, Huddersfield, West Yorks. Tel: Callers by appointment only. JABCO LOPT TESTER This instrument is now used in hundreds of Service Workshops and Manufacturers with household names all round the world. Saving countless hours in checking Line 0.P stages and the unnecessary fitting of new LOPTS. Mains operated. Straight forward indication of good or bad by Red & Green Leds. No controls to set up. Instruction booklet on testing many common Lopts in situ including jellypots inclusive. C.W.O. delivery 3 days. 18 overseas post by sea. 21 airmail. J. BAKER & CO. 1, Old Shoreham Rd., Southwick, Sussex BN4 4RD. Tel. Brighton TRADE COLOUR TV'S MOST MAKES & SIZES FROM 10. DISCOUNTS 5% & 10`)/0 OFF FOR 5+ & 10+. MONDAY -SUNDAY. Tel: Southampton WIZARD DISTRIBUTORS MANCHESTER SPECIALIST DISTRIBUTORS TO THE TRADE OF T.V. &VIDEO SPARES. WE STOCK A FULL RANGE OF PARTS & COMPONENTS INCLUDING C.R.T's RANK - THORN - PHILIPS - ITT - DECCA - GEC ETC. TRADE COUNTER OPEN: CATALOGUE ON REQUEST. Mail Order Enquiries Welcomed EMPESS STREET WORKS, EMPRESS STREET, MANCHESTER M16 9EN. TEL: CURE VIDEO INTERFERENCE Stop interference from spoiling your off -air recordings or breaking into your pre-recorded playbacks. Most TVI filters are ineffective; our braid -breaker design really works. They are recommended by Sony and supplied to British Telecom. For details ring or write: Elldee Technology, (Dept. NI), Freepost, Lowestoft, Suffolk NR32 3BR. Telephone: Trade enquiries we/come SUFFOLK TUBES LIMITED 214 Purley Way, Croydon, Surrey. Tel: /2/3/4 SUPPLIERS OF MONO AND COLOUR TUBES TO MAJOR RENTAL COMPANIES. ALL COLOUR TUBES HOT PUMPED AT 385c AND REBANDED TO BRITISH STANDARD CLAUSE " and 22" TUBES APPROVED. OTHER TYPES PENDING. BRITAINS LARGEST INDEPENDENT REBUILDER FOR 21 YEARS. ORDER FORM PLEASE WRITE IN BLOCK CAPITALS Please insert the advertisement below in the next available issue of Television for insertions. I enclose Cheque/P.O. for (Cheques and Postal Orders should be crossed Lloyds Bank Ltd and made payable to Television) NAME Send to: Classified Advertisement Dept. TELEVISION ADDRESS Classified Advertisement Dept, Room 2612, King's Reach Tower, Stamford Street London SE1 91.S. Telephone Rate 33p per word, minimum 12 words. Box No. 60p extra. Company registered in England. Registered No Registered Office, King's Reach Tower, Stamford Street, Condon SE1 9LS. APR/ TELEVISION APRIL 1983

57 -4 I < WIRELESS COMPANY> NOSTALGIA -COLLECTING s Publishers of 'The Antique Wireless Newsheef (Sample on Request) Suppliers of: Valve Radio sets & Amplifiers Valves,Components Repairs & Restorations Service Data & Manuals Historical Data New and Used Books/Magazines The complete service for the collector and enthusiast of Vintage Radio. THE VINTAGE WIRELESS COMPANY 64 Broad StreetStaple HiLLBristolBS16 SNL ThLBristol(0272) hourAnsaphone, Mondays. JAPANESE COLOUR TVs, Hitachi, Sony, Panasonic, Mitsubishi, Toshiba, Sharp. Colourland TV. Trade Only CAMPBELL ELECTRONICS LTD. Distributors of specialist spares to radio and television service depts. We stock semiconductors, I/Cs, special T.V. and audio spares, service aids, rebuilt CRTs etc. Fast off the shelf delivery of stock items. Send S.A.E. or telephone for full catalogue and price list. CAMPBELL ELECTRONICS LTD., Unit 5, Heath Hill Estate, Dawley, Telford, Shropshire. Telephone Telford (0952) OXFORD T.V. SALES WORKING COLOUR SETS FROM 40. BUSH, G8, DECCA ETC. EX -EQUIPMENT TUBES 8. TEL: WITNEY AERIALS AERIALS & ACCESSORIES QUALITY components at competitive prices. UHF 10 element from element from FM2 from E2.40. FM4 from Lashing Kits from Wall Bkts. from 85p. Masts available 2' to 20'. Aluminium coax plugs from. Coax cable from Full range of Accessories and Amplification Equipment available, Comprehensive price list on request. S.C.S. AERIALS (Aerial Distributors) 14 Tanners Crescent, Hertford, Herts. SG13 8DS Tel: BOOKS & PUBLICATIONS ANY PUBLISHED, full-sized service sheet by return 2 + L.s.a.e. CTV/Music centres 3. Repair data with all circuits, layouts, etc. Your named TV or Video Free mag. all orders, queries: TIS (TV), 76 Churches, Larkhall, Lanarkshire. WANTED WANTED PHILIPS/PYE Gll Colour TVs, any quantities. Hornchurch 58513, Mr. Morris. COURSES CONQUER THE CHIP... Master modern electronics the PRACTICAL way by SEEING and DOING in your own home. Write for your free colour brochure now to British National Radio & Electronics School, Dept. C4, Reading, Berks RG1 1BR. STEVE BEECHING will be holding another 2 day training Course, on 14th and 15th May If you would like details, please ring or send a letter to: NEWARK VIDEO CENTRE, 108 London Road, New Balderton, Newark, Notts. Tel: Newark FOR SALE SPECIAL CLEARANCE Colour TV's good working order 25 each. Any quantities, most makes and sizes available. Complete non -workers 10 each. Mono sets 2 each. Spare parts available. Tel: (0203) or (041) SERVICE SHEETS TRADE TELEVISIONS Wide range of used sets in good cabinet condition. Plenty of working sets - try ours! Delivery arranged anywhere. B.T.V., 39 St. Stephen's Road, Birmingham B29 7RR. Tel: WORKING PANELS THORN 3K -3K5 power, scan. 7. Others available Ext AVO8 MK III 13 Vols R.T.V. servicing books, 7 Vols Television Magazine and many spares. Offers REGUNNED Al TUBES 22" Mono 11. PIL in stock. Ring first , seven days till 8 pm. TELEVISIONS, closing down clearance. Colour, Mono's, (1500s), spares, parts etc. 300 o.n.o. Ring Dave (Croydon). VIDEO CAMERA FULLY INTERLACED ONLY 3" x x 6" better than 450 line resolusion. Including 16mm lens. ONLY 160 inc. P&P. 24" Monitor 190 plus delivery. I.T.S. 97 Marton Drive, Blackpool, Lanes. Tel: SITS VACANT TELEVISION ENGINEER METROVIDEO ARE LOOKING FOR A keen intelligent Television Servicing Engineer capable of repairing colour monitors & TV's and anxious to progress into industrial video equipment. We are a busy service company based in S.W. London, handling the needs of several large organisations using mainly Barco, Sony & JVC Monitors. Good opportunity for the right self -motivated person. Clean driving licence essential. Tel: BRIAN ROTTGER, METROVIDEO SITS WANTED MALE WANTS JOBS in London TV & Video Engineering C & G Part I & II. Tel `-\ TECHNICAL INFORMATION SERVICE SERVICE SHEETS: full size by return - radio, mono, etc. 2 + large sae. CTVs & Music Centres from 3. SERVICE MANUALS: Sole suppliers most obsolete equipment. Everything stocked to latest releases. Fantastic stocks CTVs/Videos. E.g. A ; Autovox (early) Tyne 5000/6000 Series COMPREHENSIVE TV REPAIR COURSE - Complete data almost every fault. - Huge beginners section. - Only TV REPAIR MANUALS - All 12 for Mono portables (new) Early VCR, CIRCUIT DIAGRAM COLLECTIONS IN HUGE BINDERS: British CTV (3) 42.50; Foreign CTV (2) 27; Early VHS/Phillips video 15; Mono TV standard + portables 29. REPAIR SYSTEMS (REPAIR DATA, CIRCUITS, ETC): Video 1, 24.50; Foreign CTV, 40; Mono TV, SAVE 12 - BRITISH CTV ONLY 60 - LIMITED TIME; Complete integrated TV Repair System 160. Quotations/free magazine/price fists/etc for large sae. 2 plus 8" x 10" S.A.E. for service sheet and manual catalogues with 4 vouchers. PHONE FOR FAST QUOTES - Open 4-6 daily, 11-1 weekends. T.I.S., 76 CHURCH ST., LARKHALL, LANARKSHIRE ML9 1HE. 30,000 SERVICE SHEETS IN STOCK. COLOUR MANUALS ALSO AVAILABLE TV Monos, Radios, Tuners Tape Recorders, Record Players Transistors, Stereograms & Music Centres SAE. Also Colour Available. Car Radios SAE. All Radiograms State if Circuit will do if sheets are not in stock. All TV Sheets are full-length 24 x12, not in Bits & Pieces. All other Data full -lengths. All sheets from 2.00 except Colour. OLD VALVE Radios SAE 9" x 3". MAIL ORDER C. CARANNA, 71 BEAUFORT PARK, LONDON NW11 6BX S.A.E. SANDHURST PUBLICATIONS Television Service Sheet Specialists Workshop Manuals, large selection of Japanese and European TV Sheets. Callers pm. Upper Floor. Send S.A.E. for Catalogue and Enquiries: 49C Yorktown Road, Sandhurst, Camberley, Surrey GU17 7AG. BELL'S TELEVISION SERVICES for service sheets on Radio, TV, etc plus SAE. Colour TV Service Manuals on request. SAE with enquiries to B.T.S., 190 Kings Road, Harrogate, N. Yorkshire. Tel. (0423) SERVICES VIDEO, HI FL TELEVISION Servicing by highly experienced engineers. Trade contracts required. Capital Electronics MISCELLANEOUS BURGLAR ALARM EQUIPMENT. Latest discount catalogue out now. Phone C.W.A.S. ALARM TELEVISION APRIL

58 DIODES OA 47 OA 90 IN 60 IN 541 IN 914 IN 2069a IN 2070 IN 4001 IN 4002 IN 4004 IN 4005 IN 4006 IN 4007 IN 4448 IN 4742 IN 4722 IN 4751 IN 5235 IN 5254 IN 5392 IN 5401 IN 5928B IA 5401 IAV 30 IM 72Z55 IR 106a IR 3051 IS 164 IS 921 IS 3011a IS 3072a IS 5024a IITT S ITT 923 ITT 1075 ITT 2001 ITT 2002 ITT 4150 ZE 1.5 ZF 3.0 ZF 3.3 ZF 4.3 ZF 10 ZF 11 ZF 12 ZF 15 ZF 33 ZF 43 ZF 47 ZF 82 ZPD 3.9 ZPD 4.7 ZPD 5.6 ZPD 10 ZPD 47 ZPY 8v2 ZPY 12 ZPY 16 ZPY 24 ZPY 43 ZPY 47 ZPY 5 ZTE 26 ZTK 22 ZTK 33 ZTK 33a ZTX 102c ZTX 107 ZTX 108c ZTX 109k ZTX 213 ZTX 341 ZTX 342 ZTX 384 ZTX 451 ZTX 550 ZW 13 ZW 27 ZW 43 ZW 310 ZX 68 ZY 47 ZY 72 AA 112 AA 113 AA 143 AA 144 BA 102c BA 157 BA 159 BA 173 BA 182 BA 201 BA 202 BQ 243 BA 248 BA 316 BAV 10 BAV 21 BAW 21 BB 103 BB 105A BB 105B BB 1050 BB 1 21a BZX 46c22 BZX 61c110 BZX 61c15 BZX 61c20 BZX 61c220 BZX 70c33 BZX 79c4v7 BZX 79c5v6 BZX 79c6v2 BZX 79c6v8 BZX 79c8v2 BZX 79c12 BZX 79c22 BZX 79c30 BZX 79c43 BZX 79c47 BZX 83c4v3 BZX 83c5v6 BZX 83c8v2 BZX BRC 83c13 BZX 83c20 BZX 83c27 BZX 83c33 BZX 84c6v8 BZX 85c8v2 8p Sp Sp Sp Sp 109 Sis inp Sp op li lop P 10o 1,02 jol 5,4212 lop' lop I P lop lop n"0p P 1 Blp lop I P 109 lop' lop LOP joil,iop jol. lop LOP 'P 1n0,p 1,,...01) lopi Sp SP 1 P I P 12p ilep. SOp lop top h" lop tlp 02 "SP Op Op 8P Op el) top 1OP lop 1Sp 6P OP top P Op gp Ilp 8p 13p 8p SP Op._01, lop lop 1 P lop BZY 88c0v7 BZY 88c3v9 BZY 884v3 lop BZY 88c4v7 BZY v BZY 88 6v2 BZY 88c12 BZY 88c22 CV P. Y 716 Y 730 Y P Y 860 Y 933 Si' 1' P All diodes at in this list 20 of one type Alternative diodes eg IN 4448/ BY 298 will be sent should we be out of stock. L R 1038,_'"I' R 1039 R 2008b ''''P 1 R 2010b 1 R R p R p R 2323 isp R 2461 LI R R 2443=13D124 R ,,,_.23 R2737=TIP31A 72 R2738=TIP41 :`,:12 R2775=TIP41c ",2 R2928=BU 208 UuP R R3129=TIP47 4 1:1 R p R 3019 op BU p BU 105/04 80p BU BU 124 BU 126 sop BU 137 sop BU 180a 65p BU p BU BU 206 L1 BU BU P BU 208a 51 BU BU BU 407 BU 426V 6 P BU BU p BUX 84 BUW 84 BUY 71 BSX 19 BSX 20 30P LI 17p I7P TIC 106a TIC 116d TIC 116n 35p TIC 126 TIC 206m TIC 226m 3 P TIC 236m TICV 106D (T092 case,_ 2A/400V) lop TIP 29C/A TIP 30 TIP 31A/B TIP 32 TIP 33 SOP TIP 34 50P TIP 35 'OP TIP 36 SOP TIP 41 41c TIP TIP 100 TIP 112 TIP 117 TIP 120 TIP p TIP 130 TIP 131 TIP 136 TIP 640 II Tip 2955 F247 MJE 1300S MJE 2955C3 MV 2209 SP 8385 Voltage Regulators 6V/78M06v 8V/79M08c 12V/MC V/LM 340T12 18V/MC78M18 24V/78M24 ' TIS 90 TIS 91 TIS 92 U U 3832 U 3845 MR 856 MR 508 MR 501 MR 502 MR 852 MR 854 BYF 1202 BYF 1204 BYF 3123 BYF 3126 BYF P BYX 36/600 BYX 38/ / BYX 38/600 BYX 55/350 top BYX 71/350 BYX 71/600 BYX 72/300 BYV 95 8p BYV 96D lop BYZ 106 BPW 41 BFY 50 BFY 90..._. PHILLIPS DIY HOME SECURITY ALARMS KITS Send for details. Prices 54 to 112. Vi,..- 1 ' "s., OL :1,.. le fe- *trolgai0j-. '.- ' --'.". 7, - MARDAVE MODEL RACING CARS Nickel Cadmium Battery driven Please send for details saudia Various Tools and Accessories Sellotape PVC Black 25mm x 20M 50mm x 20M 70p Telescopic aerials (radio) 1 Xcelite pliers 3.90 Xcelite snips 5 Xcelite cutters 3.90 GKN Supascrew kits; 180 items in box with British made screwdriver. VU meter Pull up large aerial Portable TV aerial Was ONLY p 75p 75p screwdriver Phillips snips 2 baby alarm/intercom with long leads 5 Phillips universal battery tester/charger, fuse/bulb tester 5 Volt/ohm test meters 1000 ohm/volt 5 Eisenmann NICAD CHARGER 5.5 V/150 ma 2 4" microphone/speaker " Ferrite rod with LW/MW coils BYW 56 2A/1000v 8p BF 960 MIP BFR diode XK 3123 sop Neon 2 way BZY 93 5 P BZV 15/12 15/18 BZV 15/30 3 P BZW 70c6v2 1A/1600v diode lop Al diode 10P i" x Mitsumi tape motor 75p Sankyo tape motor 7Sp Remo Swiss made 25Orpm/240V motor very small 75p Infra red led GEC remote panel. Main LD57CA transformer 3/ic SAA 1025/SN 74141/TBA Mono scan coil 13 G 8 transductor 1 Thorn 4000 tube base 4 Al pots Thorn K5 Lin pot with 40mm spindle BRIDGES KBL 005 KBL 02 KBP 04 W004 W005 Hitachi portable complete SENDZ Chassis 12 AT 2076/55 GEC split ditransformer ode 10 AT lard 2048/11 LOPTI Mul v W/W 25 watt TV Sound Tuner Kit, ideal for TV sound on your Hi-Fi 9.50 COMPONENTS Front End Music Center. VHF/MW/LW 13"x 3i" 5 Output Stage for music center 5 Both items 9 circuit supplied (as pre - vious ad) SONY 1400KV Chroma Panel SONY 1400KV 6 Tuner unit 3.50 SONY 1400KV Touch button unit TV books/electronic Systems/First steps into TV/Guide to Printed Circuits. Special offer ALL Bishopsteignton, Shoeburyness, ESSEX SS3 8AF SAME DAY SERVICE All items subject to availability. No Accounts : No Credit Cards Postal Order/Cheque with order Add 15% VAT, then P+P Add Postage for overseas Callers: To shop at 212 London Rd., Southend. Tel TELEVISION APRIL 1983

59 SENDZ COMPONENTS D. Whitworth, 63 Bishopsteignton, Shoeburyness, Essex SS3 8AF. Telephone: ADD VAT 15%, P&P. Goods despatched on receipt of order. No Credit Cards Taken. Shop at 212 London Rd., Southend. Transducer Hand Set insert, crystal, tranducer, 11C SAA 1124 & lead 3.50 THORN 4000 ultra sonic hand set insert with 7 buttons (no case) 5 ECL2060 on panel. New Thorn thick film. 00S1 012 E004 00S1 012 E B D Rankfroshiba preh unit Push button unit preh 6 Push button VHF/UHF for v/cap. GEC-Decca type Push button for CVC5 ITT Push button unit for GEC 2040 and ELC 1043/ Mains Droppers Pye R 3500 Thorn 6/1/100 Thorn 50/17/1K5 120/20/20/48/ /10/6 for Thorn /320/70/39 Thorn 50-40R -1K5 Aerial Socket and Lead 60p p Pye, Thorn, ITT, Thyristor, Philips GI p Rank Toshiba Tube Bases Speakers 6 x4g11 25 ohm 51x24 3 ohm 5x3 80 ohm 5x3 50 ohm 5x3 35 ohm 5x3 15 ohm 6x4 15 ohm 7x3 70 ohm 5x3 Bohm 7x3 16 ohm 8x5 Bohm 2r dia 8 ohm 3" dia 8 ohm BY 127 BY 133 BY 134 BY 164 BY 176 type BY 179 BY 184 BY 187 BY 190 BY 194 BY 196 BY 198 BY 204/4 BY 206 BY 210/400 BY 210/600 BY 210/800 BY 223 BY 226 BY 227 BY 229/400 BY 237 BY 254 BY 255 BY 296 BY 298 BY 299 BY 527 F 247 XK 3123 Thorn Al Diodes 70p 70p 80p 70p 75p 75p Sp 8p 5p Sp Sp Line Transformers 08 Trans. Philips Split Diode CVC820 Split Diode ITT CVC40 Split Diode ITT GEC Pye mono 3.00 Rank mono T704A 0.50 CVC32 ITT 7.50 EHT Split Diode Leads Triplers 11 TEZ Rank Thorn 5.00 KT CVC G9 Philips 4.00 GEC Thorn GEC 3.50 G8 Philips 4.50 Decca LP1194 Pye Grundig TVK TB THY 4.00 D22 for Pye 18" colour portable 4.00 LP 1193/ BG 100/ BG 100/ tripler 3.50 New Philips Infra Red Transmitter 9ch & Vol. & brightness change 7.00 THORN Tuner Panel. 6 Slider pots, Knobs, touch button. Ultrasonic transductor, ICs, components & mains switch 3.75 GEC Portable Line Trans Philips Infra -Red (full remote transmitter) Philips KT3 16C928/20C934 Pye KT3 7228/7324 K12 26C 797/1ST 66K Triplers MLO G11 Tuner Units G11 6 Button Key Switch Gll E/W Transformer GI 1 Line OSE Tran. Gll Transient Suppressors 245V 10 for G11 Scan Coils KT3 AE Sockets Thorn Frame Panel Thorn Power Supply Thorn Line OP Panel NPN PNP 80V 6 Amp TO66 O.P. Trans. pair GEC IC CBF SN SN1682 each Thorn 3500 IF Panel NEW 3.00 Thorn Tuner Panel 6-100K Pots & Components NEW No Tuner button 100K pots + cursors on panel for varicap tuning 1.50 THORN 1600 mains lead: switch: 3 slider assy button touch tuner BBC1/2 ITV1/2 video with is SAS 560T/ 570T 7.00 Control panel 5 sliders + mains lead 1.50 Tube base + base unit for 820 Euro chassis 4 00 CVC 9 IF panel and decoder 7.00 GEC Line 0/P Trans. & Rec Stick for Portable 3.00 CVC 20/25/30/35/40 decoder panel 10 CVC 20/25/30/35/40 decoder panel (untested) 5 CVC 40/45 IF panel 5 Mains Panel with switch and lead 1.50 Thom push button unit & cable form 1.50 International Rectifier EHT Diodes G770/HV34 6KV 6A/600V Stud Diodes EHT Rectifier 6A/1000V Stud Diodes wire ends 16Kv SKE 1/02 25A473 PNP C/P 3 for Sp Mains in V A.C. 50Hz Adaptor. For black and white camera. Power consumption: 12V A. Output voltage: 14V D.C. Dimensions 150mm (w) x 80mm (h) x 120mm (d). Accessories: Mains lead and video/audio remote cable (2 metres) 5.50 Rec & Trans Gil Ultrasonic t/text transmitter G26C 674/02 G22 C66/02 19 Infra Red (full ramote transmitter) Dynatron TV CTV 62, 63, K Transducer PHILIPS NE511N 1.20 LM337M Reg. Thorn T605 1V NPN TO66 80V 6A 20 GEC Black Spark Gaps Gil Line Driver Transformer 35p 2 SD350A BU208A Gll IF Detector 3.00 Gll Teletext Transmitter BG200/43 Tripler 3.00 DECCA IF Gll Time Base Panel AEC V/Cap Resistor Unit UHF with IC SAS660 SAS Thorn 900 Sound OP Panel NEW U321 T/Unit on Panel Cum 40 ITT 6.00 Z714 RANK IF Panels 6MHz 1 I.C. SL437F 3.00 Z909B RANK IF Panels Export 5.5MHz 2 LC's TBA1205B TCA2705Q 2.50 Z743 RANK IF Panel Export 5.5MHz 3 I.C.'s TBA750+SC9504P+ SC9503P 1.50 Tuner Unit VHF Sylvania GTR Videon MTS900 BIP VHF 2.50 Gll dynamic correction panel 6 CVC 20 Front panel with sliders + mains input panel 4 THORN 3500 Tuner panel (ELC 1043/05 + pots) 7 CVC 40 PUSH BUTTON ASSY with sliders: complete with lamp assy + pots 14 CVC 5 Mains on/off + 5 pots 2 GEC Convergence panel (We have 1000's) to clear 1 Universal Focus. Fits Pye, Thorn and Decca Units. Large Type Decca Small ITT Small for use with Split Diode Thorn 3500 Focus Unit TV11 Remo TV12SP TV13 TV14 TV18 TV20 TV30 TV45 NEW & COMPLETE wn H ALL IC's & GPO PLUG VIEWDATA DECODER PANELS (MALLARD) NORMALLY 150 to clear OS (no data supplied) Condensers 1500/ / / /18 470/25 680/ / / / / / / / / /35 220/40 400/40 680/ / /40 200/ / / / / /40 750/ / / / /50 15/ /63 250/64 140/ / /160 GI /210 scan coil correction.1/250 Gll 0.47/250 2,2 250v 4n7/250 tested 5KV 22/250 47/ / /250 GEC600/ /250 8/300 4/350 8/350 75p 75p SOp p Sp Sp Sp 5p 2Sp 2Sp 35p 2Sp Sp 5p 60p Sp 5p Sp Infra Red and Ultrasonic Gll Teletext Decoder Panel 30 RANK & ITT Mains Remote On -Off Switch (720R) 1.50 RANK & In' Mains Remote Switch 2865 ohm 1.50 Gll Mains Switch ITT Mains Switch 4 amp GEC Mains Switch 4 amp Petrick Mains Switch 4 amp G8 Mains Switch 75p Mains Dropper PYE 3R5+15R+45R SOp Thyristor 600/4 amp C106/2 24p Gll Preh Red LED P/Button for C.H. Change 2SC2073 on Heat Sink 150 NPN 1.5 Amps 7p RANK TOSHIBA Transductors TPC-2011 Remote Unit THORN 11 I.C. Mains Transformers Relay & 5 volt Reg & Component Unit 2.25 Thom I.C. board with 11 various sn 74 LC.'s 1 CVC 5 Mains on/off +250K+100K+500K+50K+500K Pot on Panel /300 16/350 50/ / /350 22/ /385 CVC 820HT 0.1/400.56K/400v 8/400 33/ / /400 33/ / / / / / / / /1500 1n8/1500 2n2/1500 9n1/ /1500 G /2KV 0.1/2KV 10n/2KV 3n9/2KV 210/8KV /2KV 5n2/2KV 7500pf/2KV 4n7/2KV 8n2/2KV / /4KV 4.7nf/5KV 180/8KV 270/8KV 1000/10KV 1200/12KV Multi -Caps Thom /100/100/350v KT3/200/25/25/385v 47/220/350v 150/150/100/100/100/ 320v 2500/2500/63v 470/470/250v 150/200/200/300v 100/200/325v 400/200/200/350v SOp 60p sop loop Sp p p /350v + 300/100/32/ 300v /200/100/32/350v /47/350v 60p 100/300/200/100/16/ 350v /100/100/375v /100/35v 60p 150/150/100/100/325v / /200/100/16/ 275v 2.00 FIT Panels CMA 10 CMA 11 CMA 30 CMA 40 CMC 10/2 CMC 15 CMC 16 CMC 19 CMC 45 CMC 47 CMC 54 CMC 56 CMC 58 CMC 59 CMC 67 CMC 67/2 CMC 68 CMD 40 CMF 25 CMF 40 CMH 10 CMH 31 CMK 12 (untested) CMN 20 CMN 40 CMP 10 CMP 11 CMP 40 CMS 11 CMS 40 CMU 14 CMU 30 CMU 40 CMU 45 VMC 34 VMC MOO 7.00 E